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2: Tests of Significance Throughout this assignment you will review mock studies. You will needs to follow the directions outlined in the section using SPSS

2: Tests of Significance Throughout this assignment you will review mock studies. You will needs to follow the directions outlined in the section using SPSS and decide whether there is significance between the variables. You will need to list the five steps of hypothesis testing (as covered in the lesson for Week 6) to see how every question should be formatted. You will complete all of the problems. Be sure to cut and past the appropriate test result boxes from SPSS under each problem and explain what you will do with your research hypotheses. All calculations should be coming from your SPSS. You will need to submit the SPSS output file to get credit for this assignment. This file will save as a .spv file and will need to be in a single file. In other words, you are not allowed to submit more than one output file for this assignment. The five steps of hypothesis testing when using SPSS are as follows: 1. State your research hypothesis (H1) and null hypothesis (H0). 2. Identify your significance level (.05 or .01) 3. Conduct your analysis using SPSS. 4. Look for the valid score for comparison. This score is usually under 'Sig 2-tail' or 'Sig. 2'. We will call this \"p\". 5. Compare the two and apply the following rule: a. If \"p\" is < or = significance level, than you reject the null. Be sure to explain to the reader what this means in regards to your study. (Ex: will you recommend counseling services?) * Be sure that your answers are clearly distinguishable. Perhaps you bold your font or use a different color. This assignment is due no later than Sunday of Week 6 by 11:55 pm ET. Save the file in the following format: [your last name_SOCI332_A2]. The file must be a word file. t Tests t Test for a Single Sample (20 points) Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in #1 in the Data View window. In the Variable View window, change the variable name to \"ADL\" and set the decimals to zero. Click Analyze Compare Means One-Sample T test the arrow to move \"ADL\" to the Variable(s) window. Enter the population mean (17) in the \"Test Value\" box. Click OK. 1. Researches are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living after group therapy. The researchers have randomly selected 12 depressed clients to undergo a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the average number of activities of daily living (shown below) obtained after therapy is significantly different from a mean number of activities of 17 that is typical for depressed people. (Clearly indicate each step). Test the difference at the .05 level of significance and at the .01 level (in SPSS this means you change the \"confidence level\" from 95% to 99%). As part of Step 5, indicate whether the behavioral scientists should recommend group therapy for all depressed people based on evaluation of the null hypothesis at both levels of significance. CLIENT A B C D E F G H I J K L AFTER THERAPY 18 14 11 25 24 17 14 10 23 11 22 19 t Test for Dependent Means (20 points) Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in Problem 2 in the Data View window. Be sure to enter the \"before therapy\" scores in the first column and the \"after therapy\" scores in the second column. In the Variable View window, change the variable name for the first variable to \"ADLPRE\" and the variable name for the second variable to \"ADLPOST\". Set the decimals for both variables to zero. Click Analyze Compare Means Paired-Samples T Test the arrow to move \"ADLPRE\" to the Paired Variable(s) window \"ADLPOST\" and then click the arrow to move the variable to the Paired Variable(s) window. Click OK. 2. Researchers are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living before and after group therapy. The researchers have randomly selected 8 depressed clients in a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the observed differences in numbers of activities of daily living (shown below) obtained before and after therapy are statistically significant at the .05 level of. (Clearly indicate each step). As part of Step 5, indicate whether the researchers should recommend group therapy for all depressed people based on evaluation of the null hypothesis at the .05 level of significance and calculate the measure of association. CLIENT A B C D E F G H BEFORE THERAPY 11 7 10 13 9 8 13 12 AFTER THERAPY 17 12 12 21 16 17 17 8 The t Test for Independent Samples (20 points) Once you have entered the data, click on Analyze, then on Compare Means, and then click on Independent-Samples T Test... A dialog box will appear, with your variables (student, condition, score) on the left. Your options are (a) move one or more variables into the \"Test Variable(s)\" box to select your dependent variables(s) and (b) move one of your variables into the \"Grouping Variable\" box to select the independent variables (or identify the groups to be compared). Make \"?\" the dependent variable by moving it to the \"Test Variable(s)\" box. Then make \"?\" your independent variable by moving it to the \"Grouping Variable\" box. Now, the \"Define Groups\" button is functioning, click on Define Groups and another dialog box appears. Here you must specify the two values of the condition variable that represent the two groups you are comparing. Click in the box next to Group 1 and type the number 1, then click in the box next to Group 2 and type the number 2. Now you can click Continue to return to the \"IndependentSamples T Test\" dialog box, and click on OK to run the analysis. 3. Six months after an industrial accident, a researcher has been asked to compare the job satisfaction of employees who participated in counseling sessions with the satisfaction of employees who chose not to participate. The scores on a job satisfaction inventory for both groups are listed in the table below. Use the five steps of hypothesis testing to determine whether the job satisfaction scores of the group that participated in counseling are statistically higher than the scores of employees who did not participate in counseling at the .01 level of significance. As part of Step 5, indicate whether the researcher should recommend counseling as a method to improve job satisfaction following industrial accidents based on evaluation of the null hypothesis and calculate the measure of association. NOTE: Do not forget to give a numeric value for those who participated in counseling (e.g. 0) and those who did not participate in counseling (e.g. 1). PARTICIPATED IN COUNSELING 36 39 41 36 37 35 37 39 42 DID NOT PARTICIPATE IN COUNSELING 38 36 36 32 30 39 41 35 33 ANOVA (20 points) Open SPSS Analyze the data for #1. Remember that SPSS assumes that all the scores in a row are from the same participant. In this study, there are 15 participants divided into three groups of five. Therefore, each of the 15 participants will be described by two variables, type of therapy and the number of activities of daily living performed. If \"1\" represents the group receiving individual therapy for 1 hour every 2 weeks, \"2\" represents the group receiving 1 hour of individual therapy each week, and \"3\" indicates the group receiving 2 hours of individual therapy each week, the first participant will be described by entering \"1\" in the top cell of the first column in the Data View window and \"16\" in the top cell of the second column to indicate that the participant underwent 1 hour of therapy every 2 weeks and performed 16 activities of daily living. The second participant will be described by \"1\" and \"15\Chi-Square Chi-Square Test for Goodness of Fit: Open SPSS Remember that SPSS assumes that all the scores in a row are from the same participant. In the study presented in #1, there are 20 students, some of whom have been suspended for misbehavior. The primary conflictresolution style used by each student is also entered. [Ignore the first variable in this analysis.] When you have entered the data for all 20 students, move to the Variable View window and change the first variable name to \"SUSPEND\" and the second to \"STYLE\". Set the number of decimals for both variables to zero. Click Analyze Non-Parametric Tests Chi-Square Click the variable \"STYLE\" and then the arrow next to the box labeled \"Test Variable List\" to indicate that the chi-square for goodness of fit should be conducted on the conflict-resolution style variable. Note that \"All categories equal\" is the default selection in the \"Expected Values\" box, which means that SPSS will conduct the goodness of fit test using equal expected frequencies for each of the four styles, in other words, SPSS will assume that the proportions of students each style are equal. Click OK. Chi-Square Test for Independence: Open SPSS For #2, you need to add the variable \"SUSPEND\" to the analysis. Remember that in this problem, we are interested in whether there was an association between conflict-resolution style and having been suspended from school for misbehavior. Since the analysis will involve two nominal variables, the appropriate test is a chi-square test for independence. Click Analyze Descriptive Statistics Crosstabs Since \"SUSPEND\" is already selected, click the arrow next to the box labeled \"Rows.\" Click the variable \"STYLE\" and click the arrow next to the box labeled \"Columns.\" Click \"Statistics\" and click the box labeled \"Chi-Square.\" Click Continue. Click \"Cells\" and click the box labeled \"Expected.\" Click Continue. Click OK. 1. The following table includes resolution used by 20 students. the primary method of conflict Method N of Students Aggressive 8 Manipulative 2 Passive 2 Assertive 8 a. Following the five steps of hypothesis testing, conduct the appropriate chi-square test to determine whether the observed frequencies are significantly different from the frequencies expected by change at the .05 level of significance. Clearly identify each of the five steps. The null and alternative hypotheses for this test are, H 0 : The observed frequencies are identical with the frequencies expected by change. H A : The observed frequencies are significantly different from the frequencies expected by change. Levelof significance, = 0.05. The outputs of Chi-squaretest for goodness of fit using SPSS are shown below, STYLE Observed N Expected N Residual Aggressive 8 5.0 3.0 Manipulative 2 5.0 -3.0 Passive 2 5.0 -3.0 Assertive 8 5.0 3.0 Total 20 Test Statistics STYLE Chi-Square 7.200a df Asymp. Sig. 3 .066 a. 0 cells (.0%) have expected frequencies less than 5. The minimum expected cell frequency is 5.0. Test Statistic, 2 = 7.200 Degrees of freedom, . =3 . p-value for a two tailed test is 0.066. Since p-value is greater than 0.05, we fail to reject our null hypothesis at 5% level. Therefore, at 5% level data doesn't provide sufficient evidence to support the claim that the observed frequencies are significantly different from the frequencies expected by change. b. Explain your response to some who has never had a course in statistics. We found out that the data of 20 students who suspended from school due to various reasons of misbehavior. To check whether all the four reasons are equally likely to happen or not, conducted a Chi-square test for goodness of fit that is appropriate here. The test results provide the conclusions that all the four reasons are equally likely to happen. 2. Next, researchers categorized the students based on the primary method of conflict resolution used and whether the student had been suspended from school for misbehavior. These data are presented below. Suspende d Yes No Total Aggressiv e 7 1 8 Method Manipulativ Passive e 1 1 1 1 2 2 Assertive Total 1 7 8 10 10 20 a. Following the five steps of hypothesis testing, conduct the appropriate chi-square test to determine whether the observed frequencies are significantly different from the frequencies expected by change at the .05 level of significance. Clearly identify each of the five steps. The null and alternative hypotheses for this test are, H 0 : The observed frequencies are identical with the frequencies expected by change. H A : The observed frequencies are significantly different from the frequencies expected by change. Levelof significance, = 0.05. The outputs of Chi-square test for independence of attributesusing SPSS are shown below, SUSPEND * STYLE Crosstabulation STYLE Aggressive SUSPEND Yes Count Expected Count No Count Expected Count Total Count Expected Count Manipulative Passive Assertive 7 1 1 1 10 4.0 1.0 1.0 4.0 10.0 1 1 1 7 10 4.0 1.0 1.0 4.0 10.0 8 2 2 8 20 8.0 2.0 2.0 8.0 20.0 Chi-Square Tests Asymp. Sig. (2Value df sided) Pearson Chi-Square 9.000a 3 .029 Likelihood Ratio 10.124 3 .018 Linear-by-Linear 8.319 1 .004 Association N of Valid Cases 20 a. 8 cells (100.0%) have expected count less than 5. The minimum expected count is 1.00. Test Statistic, 2 = 9.000 . Total Degrees of freedom, =3 . p-value for a two tailed test is 0.029. Since p-value is less than 0.05, we have to reject our null hypothesis at 5% level. Therefore, at 5% level data provides sufficient evidence to support the claim that the observed frequencies are significantly different from the frequencies expected by change. b. Calculate the effect size. Effect size can be measured through either Phi or Cramer's V. The output of Phi or Cramer's Vusing SPSS are shown below, Symmetric Measures Value Nominal by Nominal N of Valid Cases = 0.671 Approx. Sig. Phi .671 .029 Cramer's V .671 .029 20 . Cramer's V = 0.671. The effect size is 0.671 and it is significantly high. It indicates we have strong evidence from data to conclude that the observed frequencies are significantly different from the frequencies expected by change. c. Explain your response to someone who has never had a course in statistics. We have studied the data of 20 students who are classified by two attributes the type of misbehavior committed and whether suspended from school or not. To check whether the two attributes under study are independent or not, conducted a Chi-square test for independence of attributes that is appropriate here. The test results provide the conclusions that the two attributes under study are not independent. Suspension from School Yes No Total Conflict Resolution Assertive Other 1 6 7 Total 9 4 13 10 10 20 A Following the five steps of hypothesis testing, conduct the appropriate chi-square test to determine whether the observed frequencies are significantly different from the frequencies expected by change at the .05 level of significance. Clearly identify each of the five steps. The null and alternative hypotheses for this test are, H 0 : The observed frequencies are identical with the frequencies expected by change. H A : The observed frequencies are significantly different from the frequencies expected by change. Levelof significance, = 0.05. The outputs of Chi-square test for independence of attributesusing SPSS are shown below, SUSPENSION * CONFLICT Crosstabulation CONFLICT Assertive SUSPENSION Yes Count Expected Count No Count Expected Count Total Count Expected Count Other Total 1 9 10 3.5 6.5 10.0 6 4 10 3.5 6.5 10.0 7 13 20 7.0 13.0 20.0 Chi-Square Tests Value df Asymp. Sig. (2- Exact Sig. (2- Exact Sig. (1- sided) sided) sided) 5.495a 1 .019 Continuity Correctionb 3.516 1 .061 Likelihood Ratio 5.936 1 .015 Pearson Chi-Square Fisher's Exact Test .057 Linear-by-Linear 5.220 1 .029 .022 Association N of Valid Cases 20 a. 2 cells (50.0%) have expected count less than 5. The minimum expected count is 3.50. b. Computed only for a 2x2 table Test Statistic, 2 5.495 Degrees of freedom, . 1 . p-value for a two tailed test is 0.019. Since p-value is lessthan 0.05, we have to reject our null hypothesis at 5% level. Therefore, at 5% level data provides sufficient evidence to support the claim that the observed frequencies are significantly different from the frequencies expected by change. a. Calculate the effect size. Effect size can be measured through either Phi or Cramer's V. The output of Phi or Cramer's Vusing SPSS are shown below, Symmetric Measures Value Nominal by Nominal Phi Cramer's V N of Valid Cases = 0.524 Approx. Sig. -.524 .019 .524 .019 20 . Cramer's V = 0.524. The effect size is 0.524 and it is significantly high. It indicates we have strong evidence from data to conclude that the observed frequencies are significantly different from the frequencies expected by change. b. Explain your results. We have studied the data of 20 students who are classified by two attributes the type of misbehavior committed and whether suspended from school or not. To check whether the two attributes under study are independent or not, conducted a Chi-square test for independence of attributes that is appropriate here. The test results provide the conclusions that the two attributes under study are not independent. The deadline for this assignment is 11:59 PM EST on Sunday of Week 8 SPSS ASSIGNMENT #5 Single Sample & Dependent Samples t Tests SPSS instructions: (For more details, check the links provided under \"Course Materials\" in the Course Overview Folder (under Lessons). t Test for a Single Sample: Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in #1 in the Data View window. In the Variable View window, change the variable name to \"ADL\" and set the decimals to zero. Click Analyze Compare Means One-Sample T test the arrow to move \"ADL\" to the Variable(s) window. Enter the population mean (14) in the \"Test Value\" box. Click OK. t Test for Dependent Means: Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in Problem 2 in the Data View window. Be sure to enter the \"before therapy\" scores in the first column and the \"after therapy\" scores in the second column. In the Variable View window, change the variable name for the first variable to \"ADLPRE\" and the variable name for the second variable to \"ADLPOST\". Set the decimals for both variables to zero. Click Analyze Compare Means Paired-Samples T Test the arrow to move \"ADLPRE\" to the Paired Variable(s) window \"ADLPOST\" and then click the arrow to move the variable to the Paired Variable(s) window. Click OK. Review the five steps of hypothesis testing and complete the following problems. Be sure to cut and past the appropriate result boxes from SPSS under each problem. 1. Researchers are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living after group therapy. The researchers have randomly selected 12 depressed clients to undergo a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the average number of activities of daily living (shown below) obtained after therapy is significantly different from a mean number of activities of 14 that is typical for depressed people. (Clearly indicate each step). Test the difference at the .05 level of significance and, for practice, at the .01 level (in SPSS this means you change the \"confidence level\" from 95% to 99%). In Step 2, show all calculations. As part of Step 5, indicate whether the behavioral scientists should recommend group therapy for all depressed people based on evaluation of the null hypothesis at both levels of significance and calculate the effect size. CLIENT A B C D E F G H I J K L AFTER THERAPY 17 15 12 21 16 18 17 14 13 15 12 19 Step 1: Restate the question as a research hypothesis and a null hypothesis about the populations. Population 1: Depressed people who undergo therapy Population2: Depressed people in general (those that do no undergo therapy) Suppose denotes the mean number of activities of daily living obtained after therapy for depressed people. (Ho: = 14) (Ha: 14) The null and alternative hypotheses are: N: The populations of depressed people, who go through group therapy, perform the same number of activities of daily living, than the population of depressed people who do not get the therapy. A: The populations of depressed people, who go through group therapy, perform a greater number of activities of daily living, than the population of depressed people who do not get the therapy. Step 2: Determine the characteristics of the comparison distribution: For this example population mean=14 (number of activities typical for a depressed person) 12,12,13,14,15,15,16,17,17,18,19,21 N= 12 Mean = /N = 12+12+13+14+15+15+16+17+17+18+19+21= 189 189/12=15.75 Mean = 15.75 Have to determine the variance of the population of individuals Use formula for estimated population variance S = (X-M) /df (X-M) = (17-15.75) + (15-15.75) + (12-15.75) + (21-15.75) + (16-15.75) + (18-15.75) + (17-15.75) + (14-15.75) + (13-15.75) + (15-15.75) + (12-15.75) + (19-15.75) = (1.25) + (-0.75) + (-3.75) + (5.25) + (0.25) + (2.25) + (1.25) + (-1.75) + (-2.75) + (0.75) + (-3.75) + (3.25) = (1.5625) + (0.56) + (14.0625) + (27.5625) + (0.0625)+ (5.0625) + (1.5625) + (3.06) + (7.56) + (0.56) + (14.0625) + (10.5625) = 86.24 df= N-1=12-1= 11 df = 11 S = (X-M) /df S = 86.24/11= 7.84 Estimated population variance is 7.84 (standard deviation: 7.84 = 2.80) Variance of the distribution of means: SM= S/N S= 7.84 N=12 S M = 7.84/12 S M = 0.6533 Now we can calculate standard deviation of the distribution of means using formula: SM= S M SM= 0.93167 = 0.808 The shape is a t distribution with 11 degrees of freedom Step3: Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Here the level of significance is assumed to be 0.05 and 0.01 The null hypothesis should be rejected at cutoff score +2.201 or -2.201 at 5% and +3.106 or -3.106 at 1% Step 4: Determination your sample's score on the comparison distribution. Used formula: The test statistic is t= (M-PopM)/SM = (15.75 - 14)/0.808 = 2.165 Step 5: Decide whether to reject the null hypothesis. For the example, the cutoff t score is 2.201 and the actual t score was 2.165, since the t value (2.165) is less than the level of significance .05, we fail to reject the null hypothesis Ho. So we don't have sufficient evidence to conclude that the average number of activities of daily living obtained after therapy is significantly different from a mean number of activities of 14 that is typical for depressed people. Since the null hypothesis is not rejected at .05 level of significance, the null hypothesis is also not rejected at the .01 level of significance. The effect size is Effect size: (Population 1M-Population 2M)/Population SD = (15.75 - 14)/2.80 = 0.625 a medium effect SPSS Output for #1: One Sample T Test at 95%: One-Sample Statistics ADL N 12 Mean 15.75 Std. Error Std. Deviation Mean 2.800 .808 One-Sample Test Test Value = 14 ADL t 2.165 df 11 Mean Sig. (2-tailed) Difference .053 1.750 95% Confidence Interval of the Difference Lower Upper -.03 3.53 SPSS Output for the One Sample T Test at 99%: One-Sample Statistics ADL N 12 Mean 15.75 Std. Error Std. Deviation Mean 2.800 .808 One-Sample Test Test Value = 14 ADL 2. t 2.165 df 11 Mean Sig. (2-tailed) Difference .053 1.750 99% Confidence Interval of the Difference Lower Upper -.76 4.26 Researchers are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living before and after group therapy. The researchers have randomly selected 8 depressed clients in a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the observed differences in numbers of activities of daily living (shown below) obtained before and after therapy are statistically significant at the .05 level of significance and, for practice, at the .01 level. (Clearly indicate each step). In Step 2, show all calculations. As part of Step 5, indicate whether the researchers should recommend group therapy for all depressed people based on evaluation of the null hypothesis at both levels of significance and calculate the effect size. CLIENT A B C D E F G H BEFORE THERAPY 12 7 10 13 9 8 14 11 AFTER THERAPY 17 15 12 21 16 18 17 8 Step 1: Restate the question as a research hypothesis and a null hypothesis about the populations. Population 1: Depressed people who receive group therapy Population2: Depressed people whose daily activity changes from before and after group therapy Suppose D denote the mean observed differences in numbers of activities of daily living obtained before and after therapy. Ho: D = 0 (The mean difference is zero) Ha: D 0 (There is a mean difference) The null and alternative hypotheses are: N: Depressed people who receive group therapy, do not change their daily activities from before or after therapy. A: Population 1's mean difference score is different from Population 2's mean difference score of zero. Step 2: Determine the characteristics of the comparison distribution: BEFORE THERAPY AFTER THERAPY 12 7 10 13 9 8 14 11 17 15 12 21 16 18 17 8 Difference (AfterBefore) -5 -8 -2 -8 -7 -10 -3 3 N= 8 Mean = /N = Pre- 12,7,10,13,9,8,14,11 = 84 = Post- 17,15,12,21,16,18,17,8 = 124 = Diff- -5,-8,-2,-8,-7,-10,-3,3= -40 Pre Mean= 84/8= 10.5 Mean= 10.5 Post Mean= 124/8=15.5 Mean = 15.5 Diff Mean= -40/8= 5 Mean = -5 Assume a mean of the distribution of the means of difference scores of 0. Have to determine the variance of the population of difference scores using formula for estimated population variance S = (X-M) /df PRE: (X-M) = (12-10.5) + (7-10.5) + (10-10.5) + (13-10.5) + (9-10.5) + (8-10.5) + (14-10.5) + (11-10.5) = (1.5) + (-3.5) + (-3.75) + (-0.5) + (2.5) + (-1.5) + (-2.5) + (3.5) + (-0.5) = (2.25) + (12.25) + (0.25) + (6.25) + (2.25)+ (6.25) + (12.25) + (0.25) = 42 POST: (X-M) = (17-15.5) + (15-15.5) + (12-15.5) + (21-15.5) + (16-15.5) + (18-15.5) + (1715.5) + (8-15.5) = (1.5) + (-0.5) + (-3.5) + (5.5) + (0.5) + (2.5) + (1.5) + (-7.5) = (2.25) + (0.25) + (12.25) + (30.25) + (0.25)+ (6.25) + (2.25) + (56.25) = 110 Diff: (X-M) = (-5--5) + (-8--5) + (-2--5) + (-8--5) + (-7--5) + (-10--5) + (-3--5) + (3--5) = (0) + (-3) + (3) + (-3) + (-2) + (-5) + (2) + (8) = (0) + (9) + (9) + (9) + (4) + (25) + (4) + (64) = 124 df= N-1= 8-1= 7 df = 7 S = (X-M) /df PRE: S = 42/7= 6 Estimated PRE population variance is 6 (standard deviation: 6= 2.449) POST: S = 110/7 = 15.714 Estimated POST population variance is 15.714 (standard deviation: 15.714= 3.964) Diff: S = 124/7 = 17.714 Estimated Diff population variance is 17.714 (standard deviation: 17.714 = 4.209) Variance of the distribution of means: SM= S/N PRE: S= 6 N=8 S M = 6/8 S M = 0.75 POST: S= 15.714 N=8 S M = 15.714/8 S M = 1.9675 Diff: S = 17.714 N=8 S M = 17.714/8 S M = 2.21425 Now we can calculate standard deviation of the distribution of means using formula: SM= S M PRE: SM= 0.75 = 0.866 POST: SM= 1.9675 = 1.402 Diff: SM= 2.21425 = 1.488 The shape is a t distribution with 7 degrees of freedom Step3: Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Here the level of significance is assumed to be 0.05 and 0.01 The null hypothesis should be rejected at cutoff score +2.365 or -2.365 at 5% and +3.500 or -3.500 at 1% Step 4: Determination your sample's score on the comparison distribution. Used formula: The test statistic is t= (M-PopM)/SM = (-5 - 0)/1.488 = -3.360 Step 5: Decide whether to reject the null hypothesis. For the example, the cutoff t score is 2.365 and the actual t score was -3.360, since the t value (-3.360) is less than the level of significance .05, reject the null hypothesis Ho. Therefore the observed differences in numbers of activities of daily living obtained before and after therapy are statistically significant at the .05 level of significance. The t score is greater than .01, we fail to reject the null hypothesis Ho if the level of significance is .01. Therefore, the observed differences in numbers of activities of daily living obtained before and after therapy are not statistically significant at the .01 level of significance. The effect size is Effect size = r2 = t2/(t2 + df) = (-3.360)2/[(-3.360)2 + 7] = (11.289/ (11.289) + (7))= 11.289/18.289= 0.61725 = 0.7856 a medium effect The SPSS output for #2 Paired-Samples T Test at 95%: Paired Samples Statistics Mean N Std. Deviation Std. Error Mean ADLPRE 10.50 8 2.449 .866 ADLPOST 15.50 8 3.964 1.402 Pair 1 Paired Samples Correlations N Pair 1 ADLPRE & ADLPOST Correlation 8 Sig. .206 .625 Paired Samples Test Paired Differences Mean Std. Std. 95% Confidence Interval Deviation Error of the Difference Mean Pair ADLPRE 1 ADLPOST - -5.000 t 4.209 1.488 Lower -8.519 df Sig. (2tailed) Upper -1.481 -3.360 7 .012 The SPSS output of the Paired-Samples T Test at 99%: Paired Samples Statistics Pair 1 ADLPRE ADLPOST Pair 1 Mean 10.50 15.50 N 8 8 Std. Deviation 2.449 3.964 Paired Samples Correlations N Correlation ADLPRE & ADLPOST 8 .206 Std. Error Mean .866 1.402 Sig. .625 Paired Samples Test Paired Differences 99% Confidence Interval of the Difference Mean Std. Deviation Std. Error Mean Lower Upper t df Pair 1 ADLPRE - ADLPOST -5.000 4.209 1.488 -10.207 .207 -3.360 7 The deadline for this assignment is 11:59 PM EST on Sunday of Week 5 Sig. (2tailed) .012 SPSS ASSIGNMENT #5 Single Sample & Dependent Samples t Tests SPSS instructions: (For more details, check the links provided under \"Course Materials\" in the Course Overview Folder (under Lessons). t Test for a Single Sample: Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in #1 in the Data View window. In the Variable View window, change the variable name to \"ADL\" and set the decimals to zero. Click Analyze Compare Means One-Sample T test the arrow to move \"ADL\" to the Variable(s) window. Enter the population mean (14) in the \"Test Value\" box. Click OK. t Test for Dependent Means: Open SPSS Enter the number of activities of daily living performed by the depressed clients studied in Problem 2 in the Data View window. Be sure to enter the \"before therapy\" scores in the first column and the \"after therapy\" scores in the second column. In the Variable View window, change the variable name for the first variable to \"ADLPRE\" and the variable name for the second variable to \"ADLPOST\". Set the decimals for both variables to zero. Click Analyze Compare Means Paired-Samples T Test the arrow to move \"ADLPRE\" to the Paired Variable(s) window \"ADLPOST\" and then click the arrow to move the variable to the Paired Variable(s) window. Click OK. Review the five steps of hypothesis testing and complete the following problems. Be sure to cut and past the appropriate result boxes from SPSS under each problem. 1. Researchers are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living after group therapy. The researchers have randomly selected 12 depressed clients to undergo a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the average number of activities of daily living (shown below) obtained after therapy is significantly different from a mean number of activities of 14 that is typical for depressed people. (Clearly indicate each step). Test the difference at the .05 level of significance and, for practice, at the .01 level (in SPSS this means you change the \"confidence level\" from 95% to 99%). In Step 2, show all calculations. As part of Step 5, indicate whether the behavioral scientists should recommend group therapy for all depressed people based on evaluation of the null hypothesis at both levels of significance and calculate the effect size. CLIENT A B C D E F G H I J K L AFTER THERAPY 17 15 12 21 16 18 17 14 13 15 12 19 Step 1: Restate the question as a research hypothesis and a null hypothesis about the populations. Population 1: Depressed people who undergo therapy Population2: Depressed people in general (those that do no undergo therapy) Suppose denotes the mean number of activities of daily living obtained after therapy for depressed people. (Ho: = 14) (Ha: 14) The null and alternative hypotheses are: N: The populations of depressed people, who go through group therapy, perform the same number of activities of daily living, than the population of depressed people who do not get the therapy. A: The populations of depressed people, who go through group therapy, perform a greater number of activities of daily living, than the population of depressed people who do not get the therapy. Step 2: Determine the characteristics of the comparison distribution: For this example population mean=14 (number of activities typical for a depressed person) 12,12,13,14,15,15,16,17,17,18,19,21 N= 12 Mean = /N = 12+12+13+14+15+15+16+17+17+18+19+21= 189 189/12=15.75 Mean = 15.75 Have to determine the variance of the population of individuals Use formula for estimated population variance S = (X-M) /df (X-M) = (17-15.75) + (15-15.75) + (12-15.75) + (21-15.75) + (16-15.75) + (18-15.75) + (17-15.75) + (14-15.75) + (13-15.75) + (15-15.75) + (12-15.75) + (19-15.75) = (1.25) + (-0.75) + (-3.75) + (5.25) + (0.25) + (2.25) + (1.25) + (-1.75) + (-2.75) + (0.75) + (-3.75) + (3.25) = (1.5625) + (0.56) + (14.0625) + (27.5625) + (0.0625)+ (5.0625) + (1.5625) + (3.06) + (7.56) + (0.56) + (14.0625) + (10.5625) = 86.24 df= N-1=12-1= 11 df = 11 S = (X-M) /df S = 86.24/11= 7.84 Estimated population variance is 7.84 (standard deviation: 7.84 = 2.80) Variance of the distribution of means: SM= S/N S= 7.84 N=12 S M = 7.84/12 S M = 0.6533 Now we can calculate standard deviation of the distribution of means using formula: SM= S M SM= 0.93167 = 0.808 The shape is a t distribution with 11 degrees of freedom Step3: Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Here the level of significance is assumed to be 0.05 and 0.01 The null hypothesis should be rejected at cutoff score +2.201 or -2.201 at 5% and +3.106 or -3.106 at 1% Step 4: Determination your sample's score on the comparison distribution. Used formula: The test statistic is t= (M-PopM)/SM = (15.75 - 14)/0.808 = 2.165 Step 5: Decide whether to reject the null hypothesis. For the example, the cutoff t score is 2.201 and the actual t score was 2.165, since the t value (2.165) is less than the level of significance .05, we fail to reject the null hypothesis Ho. So we don't have sufficient evidence to conclude that the average number of activities of daily living obtained after therapy is significantly different from a mean number of activities of 14 that is typical for depressed people. Since the null hypothesis is not rejected at .05 level of significance, the null hypothesis is also not rejected at the .01 level of significance. The effect size is Effect size: (Population 1M-Population 2M)/Population SD = (15.75 - 14)/2.80 = 0.625 a medium effect SPSS Output for #1: One Sample T Test at 95%: One-Sample Statistics ADL N 12 Mean 15.75 Std. Error Std. Deviation Mean 2.800 .808 One-Sample Test Test Value = 14 ADL t 2.165 df 11 Mean Sig. (2-tailed) Difference .053 1.750 95% Confidence Interval of the Difference Lower Upper -.03 3.53 SPSS Output for the One Sample T Test at 99%: One-Sample Statistics ADL N 12 Mean 15.75 Std. Error Std. Deviation Mean 2.800 .808 One-Sample Test Test Value = 14 ADL 2. t 2.165 df 11 Mean Sig. (2-tailed) Difference .053 1.750 99% Confidence Interval of the Difference Lower Upper -.76 4.26 Researchers are interested in whether depressed people undergoing group therapy will perform a different number of activities of daily living before and after group therapy. The researchers have randomly selected 8 depressed clients in a 6-week group therapy program. Use the five steps of hypothesis testing to determine whether the observed differences in numbers of activities of daily living (shown below) obtained before and after therapy are statistically significant at the .05 level of significance and, for practice, at the .01 level. (Clearly indicate each step). In Step 2, show all calculations. As part of Step 5, indicate whether the researchers should recommend group therapy for all depressed people based on evaluation of the null hypothesis at both levels of significance and calculate the effect size. CLIENT A B C D E F G H BEFORE THERAPY 12 7 10 13 9 8 14 11 AFTER THERAPY 17 15 12 21 16 18 17 8 Step 1: Restate the question as a research hypothesis and a null hypothesis about the populations. Population 1: Depressed people who receive group therapy Population2: Depressed people whose daily activity changes from before and after group therapy Suppose D denote the mean observed differences in numbers of activities of daily living obtained before and after therapy. Ho: D = 0 (The mean difference is zero) Ha: D 0 (There is a mean difference) The null and alternative hypotheses are: N: Depressed people who receive group therapy, do not change their daily activities from before or after therapy. A: Population 1's mean difference score is different from Population 2's mean difference score of zero. Step 2: Determine the characteristics of the comparison distribution: BEFORE THERAPY AFTER THERAPY 12 7 10 13 9 8 14 11 17 15 12 21 16 18 17 8 Difference (AfterBefore) -5 -8 -2 -8 -7 -10 -3 3 N= 8 Mean = /N = Pre- 12,7,10,13,9,8,14,11 = 84 = Post- 17,15,12,21,16,18,17,8 = 124 = Diff- -5,-8,-2,-8,-7,-10,-3,3= -40 Pre Mean= 84/8= 10.5 Mean= 10.5 Post Mean= 124/8=15.5 Mean = 15.5 Diff Mean= -40/8= 5 Mean = -5 Assume a mean of the distribution of the means of difference scores of 0. Have to determine the variance of the population of difference scores using formula for estimated population variance S = (X-M) /df PRE: (X-M) = (12-10.5) + (7-10.5) + (10-10.5) + (13-10.5) + (9-10.5) + (8-10.5) + (14-10.5) + (11-10.5) = (1.5) + (-3.5) + (-3.75) + (-0.5) + (2.5) + (-1.5) + (-2.5) + (3.5) + (-0.5) = (2.25) + (12.25) + (0.25) + (6.25) + (2.25)+ (6.25) + (12.25) + (0.25) = 42 POST: (X-M) = (17-15.5) + (15-15.5) + (12-15.5) + (21-15.5) + (16-15.5) + (18-15.5) + (1715.5) + (8-15.5) = (1.5) + (-0.5) + (-3.5) + (5.5) + (0.5) + (2.5) + (1.5) + (-7.5) = (2.25) + (0.25) + (12.25) + (30.25) + (0.25)+ (6.25) + (2.25) + (56.25) = 110 Diff: (X-M) = (-5--5) + (-8--5) + (-2--5) + (-8--5) + (-7--5) + (-10--5) + (-3--5) + (3--5) = (0) + (-3) + (3) + (-3) + (-2) + (-5) + (2) + (8) = (0) + (9) + (9) + (9) + (4) + (25) + (4) + (64) = 124 df= N-1= 8-1= 7 df = 7 S = (X-M) /df PRE: S = 42/7= 6 Estimated PRE population variance is 6 (standard deviation: 6= 2.449) POST: S = 110/7 = 15.714 Estimated POST population variance is 15.714 (standard deviation: 15.714= 3.964) Diff: S = 124/7 = 17.714 Estimated Diff population variance is 17.714 (standard deviation: 17.714 = 4.209) Variance of the distribution of means: SM= S/N PRE: S= 6 N=8 S M = 6/8 S M = 0.75 POST: S= 15.714 N=8 S M = 15.714/8 S M = 1.9675 Diff: S = 17.714 N=8 S M = 17.714/8 S M = 2.21425 Now we can calculate standard deviation of the distribution of means using formula: SM= S M PRE: SM= 0.75 = 0.866 POST: SM= 1.9675 = 1.402 Diff: SM= 2.21425 = 1.488 The shape is a t distribution with 7 degrees of freedom Step3: Determine the cutoff sample score on the comparison distribution at which the null hypothesis should be rejected. Here the level of significance is assumed to be 0.05 and 0.01 The null hypothesis should be rejected at cutoff score +2.365 or -2.365 at 5% and +3.500 or -3.500 at 1% Step 4: Determination your sample's score on the comparison distribution. Used formula: The test statistic is t= (M-PopM)/SM = (-5 - 0)/1.488 = -3.360 Step 5: Decide whether to reject the null hypothesis. For the example, the cutoff t score is 2.365 and the actual t score was -3.360, since the t value (-3.360) is less than the level of significance .05, reject the null hypothesis Ho. Therefore the observed differences in numbers of activities of daily living obtained before and after therapy are statistically significant at the .05 level of significance. The t score is greater than .01, we fail to reject the null hypothesis Ho if the level of significance is .01. Therefore, the observed differences in numbers of activities of daily living obtained before and after therapy are not statistically significant at the .01 level of significance. The effect size is Effect size = r2 = t2/(t2 + df) = (-3.360)2/[(-3.360)2 + 7] = (11.289/ (11.289) + (7))= 11.289/18.289= 0.61725 = 0.7856 a medium effect The SPSS output for #2 Paired-Samples T Test at 95%: Paired Samples Statistics Mean N Std. Deviation Std. Error Mean ADLPRE 10.50 8 2.449 .866 ADLPOST 15.50 8 3.964 1.402 Pair 1 Paired Samples Correlations N Pair 1 ADLPRE & ADLPOST Correlation 8 Sig. .206 .625 Paired Samples Test Paired Differences Mean Std. Std. 95% Confidence Interval Deviation Error of the Difference Mean Pair ADLPRE 1 ADLPOST - -5.000 t 4.209 1.488 Lower -8.519 df Sig. (2tailed) Upper -1.481 -3.360 7 .012 The SPSS output of the Paired-Samples T Test at 99%: Paired Samples Statistics Pair 1 ADLPRE ADLPOST Pair 1 Mean 10.50 15.50 N 8 8 Std. Deviation 2.449 3.964 Paired Samples Correlations N Correlation ADLPRE & ADLPOST 8 .206 Std. Error Mean .866 1.402 Sig. .625 Paired Samples Test Paired Differences 99% Confidence Interval of the Difference Mean Std. Deviation Std. Error Mean Lower Upper t df Pair 1 ADLPRE - ADLPOST -5.000 4.209 1.488 -10.207 .207 -3.360 7 The deadline for this assignment is 11:59 PM EST on Sunday of Week 5 Sig. (2tailed) .012

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