Questions and Answers of Essentials Of Statistics

Explain when each of the three measures of central tendency—mean, median, and mode—should be used, and identify the advantages and disadvantages of each.
A sample of n 5 5 scores has a mean of M 5 12.What is SX for this sample?a. 12 5 5 2.40b. 5 12 5 0.417c. 5(12) 5 60d. Cannot be determined from the information given 2.A sample has a mean of M 5?
If one person with a score of X 5 58 is removed from the sample, what effect will it have on the sample mean?a. The sample mean will increase.b. The sample mean will decrease.c. The sample mean will
One sample of n 5 4 scores has a mean of M 5 10, and a second sample of n 5 4 scores has a mean of M 5 20.If the two samples are combined, then what value will be obtained for the mean of the
What is the mean for the sample presented in the following frequency distribution table?a. 2.0b. 2.5c. 3.0d. 3.5
A population of N 5 10 scores has a mean of 30.If every score in the distribution is multiplied by 3, then what is the value of the new mean?a. Still 30b. 33c. 60d. 90
What is the median for the following set of scores?Scores: 1, 5, 7, 19a. 5b. 5.5c. 6d. 6.5
What is the median for the sample presented in the following frequency distribution table?a. 1.5b. 2.0c. 2.5d. 3.0
Find the precise median for the following scores measuring a continuous variable.Scores: 1, 4, 5, 5, 5, 6, 7, 8a. 5b. 5.17c. 5.67d. 6
For the sample shown in the frequency distribution table, what is the mode?a. 4b. 3c. 2.5d. 2
If the mean, median, and mode are all computed for a distribution of scores, which of the following statements cannot be true?a. No one had a score equal to the mean.b. No one had a score equal to
What is the mode for the following set of n 5 7 scores? Scores: 2, 4, 4, 5, 7, 8, 10a. 4b. 5c. 5.5d. 6
For a distribution of scores, the mean is equal to the median. What is the most likely shape of this distribution?a. Symmetricalb. Positively skewedc. Negatively skewedd. Impossible to determine the
For a positively skewed distribution with a mode of X 5 20 and a median of X 5 25, what is the most likely value for the mean?a. Greater than 25b. Less than 20c. Between 20 and 25d. Cannot be
For a negatively skewed distribution, what is the most probable order for the three measures of central tendency from smallest to largest?a. Mean, median, modeb. Mean, mode, medianc. Mode, mean,
A researcher is measuring problem-solving times for a sample of n 5 20 laboratory rats. However, one of the rats fails to solve the problem so the researcher has an undetermined score. What is the
What is the best measure of central tendency for an extremely skewed distribution of scores?a. The meanb. The medianc. The moded. Central tendency cannot be determined for a skewed distribution.
One item on a questionnaire asks students to identify their preferred costume for the school mascot from three different choices. What is the best measure of central tendency for the data from this
Although the three measures of central tendency appear to be very simple to calculate, there is always a chance for errors. The most common sources of error are listed next.a. Many students find it
A sample of n 5 9 scores has SX 5 108.What is the sample mean?
A population of N 57 scores has a mean of m 5 13.What is the value of SX for this population?
One sample of n 5 10 scores has a mean of 8 and a second sample of n 5 5 scores has a mean of 2.If the two samples are combined, what is the mean for the combined sample?
One sample has a mean of M 5 6 and a second sample has a mean of M 5 12.The two samples are combined into a single set of scores.a. What is the mean for the combined set if both of the original
A sample with a mean of M 5 8 has SX 5 56.How many scores are in the sample?
Find the mean for the scores in the following frequency distribution table:X f 6 1 5 4 4 2 3 2 2 1
In a sample of n 5 6 scores, five of the scores are each above the mean by one point. Where is the sixth score located relative to the mean?
A population has a mean of m 5 40.a. If 5 points are added to each score, what is the value for the new mean?b. If each score is multiplied by 3, what is the value for the new mean?
Solve the following problems.a. After 8 points are added to each score in a sample, the mean is found to be M 5 40.What was the value for the original mean?b. After every score in a sample is
A sample of n 5 8 scores has a mean of M 5
If one score is changed from X 5 20 to X 5 4, what is the value of the new sample mean?
A sample of n 5 5 scores has a mean of M 5 12.If one new score with a value of X 5 18 is added to the sample, then what is the mean for the new sample?
A population of N 5 10 scores has a mean of m 5 12.If one score with a value of X 5 21 is removed from the population, then what is the value of the new population mean?
A sample of n 5 6 scores has a mean of M 514.After one new score is added, the new sample has a mean of M 5 12.What is the value of the score that was added?
A population of N 5 7 scores has a mean of m 5 9.After one score is removed, the new population has a mean of m 5 10.What is the value of the score that was removed?
Find the median for the following set of scores: 1, 9, 3, 6, 4, 3, 11, 10
Find the median for the distribution of scores in the following frequency distribution table.X f 6 1 5 1 4 4 3 2 2 3 1 1
For the following sample of n 5 10 scores: 2, 3, 4, 4, 5, 5, 5, 6, 6, 7a. Assume that the scores are measurements of a discrete variable and find the median.b. Assume that the scores are measurements
Find the mean, median, and mode for the distribution of scores in the following frequency distribution table.X f 9 1 8 1 7 3 6 4 5 1
Find the mean, median, and mode for the following scores: 8, 7, 5, 7, 0, 10, 2, 4, 11, 7, 8, 7
Solve the following problems.a. Find the mean, median, and mode for the following scores.9 6 7 10 7 9 9 7 9 4 9 8 3 6 8 9b. Based on the three values for central tendency, what is the most likely
Solve the following problems.a. Find the mean, median, and mode for the scores in the following frequency distribution table.X f 5 2 4 5 3 2 2 3 1 0 0 2b. Based on the three values for central
Identify the circumstances in which the median may be better than the mean as a measure of central tendency and explain why
Using the same data set, test the research hypothesis at the .01 level of significance that there is a difference between males and females in the number of times they raise their hands in class. Do
Do the analysis manually or using the Data Analysis tools.a. Compute the correlation between motivation and GPA.b. Test for the significance of the correlation coefficient at the .05 level using a
Use the CORREL or PEARSON functions to calculate the correlation between number of books in the home and general educational level (or years of school completed, with 12 years being equal to
Includes data about level of risk for juvenile detention (from 1 to 5 with 5 being high risk), number of at-risk factors (such as poverty, truancy from school), and progress for 25 juveniles,
The data are the average amount of time the participants took on each item (Response Time) and the number of guesses it took to get each item correct (Number Correct).a. What is the regression
Create a cross-tabs table that shows average score (ranging from 1 to 100) by proficiency level (ranging from 1 to 5) for all 500 students.
Create a cross-tabs table that shows the number of level-4 athletes who are female among 1,000 students. In the table, under Gender, 1 = male and 2 = female. Pivot table time!
Find out all the descriptive statistics that are available for five scores (from 1 to 7) on a baking test for 10 culinary arts students. Make the output as coherent and attractive as you can.
You are developing an instrument that measures vocational preferences (what someone wants to do for a living), and you need to administer the test several times during the year while students are
Using the NORM.5.DlST function, compute the probability for the first raw score in Cell A2 and then copy the function down to compute the probabilities for each corresponding z score.
If you were to look at differences between two independent groups, what steps would you take using Figure 9.1?Data From Figure 9.1 True nature of the null hypothesis The null hypothesis is really
Using the test the research hypothesis at the .05 level of significance that males raise their hands in class more often than females. Do this practice problem by hand using a calculator. What is
Using the data in the file, test the null hypothesis that urban and rural residents have the same attitudes toward gun control. Use the T.TEST function to test the hypothesis. Assume that the
For your Friday afternoon report to the boss, you need to let her know if the two stores in Newark, New Jersey (your author's fair city of origin), are selling the same amount of merchandise each
During the last football season, the Brutes managed to gain an average of 203 yards per game while their opponents averaged 288 yards per game. Fire the coach?
What would it mean if a difference were statistically significant but the effect size were not meaningful?
What is the difference between a test of independent means and a test of dependent means, and when is each appropriate?
Compute the $t$ value using the Data Analysis tools and write a conclusion as to whether there was a change in tons of paper used as a function of the recycling program in 25 districts. Test the
In the following examples, indicate whether you would perform a $t$-test of independent means or dependent means.a. Two groups were exposed to different levels of treatment for ankle sprains. Which
Compute the $t$ value (do it manually, argh!) and write a conclusion as to whether there was a change in a group of families' satisfaction level (the higher the score, the more satisfied) with
Here's a tough one. For the same data where two groups are being compared, the critical value for rejection of the null hypothesis is higher for a set of dependent groups than for a set of
Ace used-car sales manager Jack has no idea whether the $\$ 100,000$ he pays for training for his used-car salespeople works. He asks Dave, the leading salesperson, and Dave says he thinks it works
Whether counseling adolescents at the beginning of the school year had a positive impact on their tolerance for other adolescents who are ethnically different from them. Assessments were made right
A comparison is shown between yards rushing for the first and last games of the season for 10 different football teams. Which team is best? And, yes, this is a trick question-can you find the trick?
Using the following table, provide three examples of a simple one way ANOVA, two examples of a two-factor ANOVA, and one example of a three-factor ANOVA. We show you some examples. Be sure to
Compute the $F$ value for a comparison among the three levels representing the average amount of time that swimmers practice weekly ( $25$ hours), with the dependent or outcome variable being
Stephen recognizes that there are different techniques for attracting attention to advertisements, and he wants to test three of these for the sample product: all color, all black-and-white, and a
The researchers want to find out whether there is a difference among the graduation rates (and these are percentages) of five high schools over a 10 -year period. Is there? (Hint: Are the years a
Contains the average sales for five stores across four seasons. Which season was the best of all for sales?
When would you use a factorial ANOVA rather than a simple ANOVA to test the significance of the difference between the averages of two or more groups?
Create a 23 experimental design that would lend itself to a factorial ANOVA.
Complete the analysis and interpret the results. It is a 2 3 experiment: There are two levels of severity, where Level 1 is severe and Level 2 is mild, and there are three levels of treatment,
Show the results of an experiment in which three levels of nutrition education and two levels of dietary intervention were tested to see their effects on a 10 -point scale, with 10 indicating the
You can find a 3 4 design with three levels of participation in after-school activities and four levels of GPA (1st, 2nd, 3rd, or 4th quartile). The outcome is success (as measured by peer rating)
Given the following information, use -Table B. 4 in Appenclix B to determine whether the correlations are significant and how you would interpret the results.a. The correlation between speed and
Discuss the general idea that just because two things are correlated, one does not necessarily cause the other. Provide an example (other than ice cream and crime!).
Betsy is interested in predicting how many 75 -year-olds will develop Alzheimer's disease and is using as predictors level of education and general physical health graded on a scale from 1 to 10 .
You're interested in predicting success in business. You're a stats star! Why not go out and collect 15 different variables and combine them to see which combination best predicts success (however
Go to the library and locate three examples of research studies in your area of interest in which linear regression was used. It's okay if a study contains more than one predictor variable. Answer
Here's where you can apply the information in one of this chapter's tips and get a chance to predict a Super Bowl winner! Coach Kent is curious to know whether the average number of games won in a
Why is the standard error of estimate or prediction higher when the predictive quality of variables is lower?
You will find scores on three variables. The outcome variable is overall health (Health)-the higher the score, the healthier the person is. The predictor variables are preference for sweets (Sweets),
Reach a conclusion as to whether number of years of training makes a good chef (and the higher the better on the Chef's Score).
Using the following data, test the question of whether an equal number of Democrats, Republicans, and independents voted during the most recent election. Test the hypothesis at the .05 level of
Using the following data, test the question of whether an equal number of boys and girls participate in soccer at the elementary level at the .01 level of significance. What's your conclusion? Gender
Of the following four research questions, which ones are appropriate for the chi-square test?a. What is the difference between the average scores of two math classes?b. What is the difference between
At the Diabetes Institute, patients are classified as compliant (they take their medication as they should) or not (they don't). A new program manager has a new idea: Have some patients continuously
Create formulas for the following in an Excel worksheet:a. Add the values of 3 and 5 to one another.b. Subtract the value of 5 from 1 O and multiply the outcome by 7.c. Average the values 5, 6, 7,
Use the AVERAGE function to add the values of 3, 5, and 7 and divide the total by 3.
What would the function look like for summing the values in Cells A 1 through AS?
What would the function look like for averaging the values in Cells A 1 through AS?
Create a worksheet with any five values in Cells A 1 through AS, name the range of these cells Test_Scores, and enter a function in Cell A6 that computes the average. Can you think of another way to
Compute the mean, median, and mode for the following three sets of scores. Do it by hand or using Excel. Show your work, and if you are using Excel, print out a copy of the output. Score 1 Score 2
Find out the average number of times children in three different classes ask a question each day of the week. What measure of central tendency did you use and why?
You are the manager of a fast-food store. Part of your job is to report to the boss at the end of each day which special is selling best. Use your vast knowledge of descriptive statistics to write
Under what conditions would you use the median rather than the mean as a measure of central tendency? Why? Provide an example of two situations in which the median might be more useful than the mean
List three variables, and how they are measured, for which you would use the mode as the most appropriate measure of central tendency.
You're in business for yourself and you have been fortunate to buy and own the website titled Havefun.com, where you sell every imaginable stupid toy (like potato guns) and games that everyone needs.

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