Chapter 13 Assignment Name Description of the Data: The data set contains part of the data for a study of oral condition of cancer patients conducted at the Mid-Michigan Medical Center. The oral conditions of the patients were measured and recorded at the initial stage, at the end of the second week, at the end of the fourth week, and at the end of the sixth week. The variables age, initial weight and initial cancer stage of the patients were recorded. Patients were divided into two groups at random: one group received a placebo and the other group received aloe juice treatment. Sample size:, n = 25 patients with neck cancer. The treatment is Aloe Juice. (See the Excel File \"Chapter 13 Dataset\" to complete the questions below.) Variable Names: ID- Patient ID TRT- treatment group: 0 = placebo; 1 = aloe juice AGE- patient's age in years WEIGHTIN- patient's weight at the initial stage STAGE- initial cancer stage, coded 1 through 4 TOTALCIN- oral condition at the initial stage TOTALCW2- oral condition at the end of week 2 TOTALCW4- oral condition at the end of week 4 TOTALCW6- oral condition at the end of week 6 Research Question: Is there a difference in oral condition at the end of week 2 and at the end of week 4? In other words, we want to know if there is a difference between two related samples. (Assume the samples are not normally distributed.) 1. What type of test will we perform? 2. What is the parametric version of this type of test? 3. List some of the pros and cons of using nonparametric tests. 4. List the assumptions for this type of analysis. 5. Are the dependent variables a continuous measurement? 6. Identify the null and alternative hypothesis. H0: H1: Now, let's perform our analysis. Refer to the output below to answer the questions. Statistical Output Descriptive Statistics N TOTALCW2 TOTALCW4 25 25 Std. Deviation 2.54 3.47 Mean 8.28 10.36 Minimum Maximum 4.00 6.00 16.00 17.00 Ranks N Negative Ranks 16 10.16 Sum of Ranks 162.50 Positive Ranks 3 9.17 27.50 Ties 6 Total TOTALCW2 - TOTALCW4 Mean Rank 25 Test Statistics TOTALCW2 - TOTALCW4 Z -2.72 Asymp. Sig. (2 tailed) .006 7. According to the analysis, what are the medians for each group? Week 2: Week 4: 8. Identify the appropriate test statistic and p-value for testing the claim that there is a difference in oral condition at the end of week 2 and week 4. Test statistic: p-value: 9. Using the analysis, calculate the effect size. r= z N r= 10. Use APA style reporting to write up your results of this analysis. ID TRT 1 5 6 9 11 15 21 26 31 35 39 41 45 2 12 14 16 22 24 34 37 42 44 50 58 AGE 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1 1 1 1 52 77 60 61 59 69 67 56 61 51 46 65 67 46 56 42 44 27 68 77 86 73 67 60 54 WEIGHIN STAGE TOTALCIN TOTALCW2 TOTALCW4 TOTALCW6 124 2 6 6 6 7 160 1 9 6 10 9 136.5 4 7 9 17 19 179.6 1 6 7 9 3 175.8 2 6 7 16 13 167.6 1 6 6 6 11 186 1 6 11 11 10 158 3 6 11 15 15 212.8 1 6 9 6 8 189 1 6 4 8 7 149 4 7 8 11 11 157 1 6 6 9 6 186 1 8 8 9 10 163.8 2 7 16 9 10 227.2 4 6 10 11 9 162.6 1 4 6 8 7 261.4 2 6 11 11 14 225.4 1 6 7 6 6 226 4 12 11 12 9 164 2 5 7 13 12 140 1 6 7 7 7 181.5 0 8 11 16 . 187 1 5 7 7 7 164 2 6 8 16 . 172.8 4 7 8 10 8 Chapter 13 Assignment Name Description of the Data: The data set contains part of the data for a study of oral condition of cancer patients conducted at the Mid-Michigan Medical Center. The oral conditions of the patients were measured and recorded at the initial stage, at the end of the second week, at the end of the fourth week, and at the end of the sixth week. The variables age, initial weight and initial cancer stage of the patients were recorded. Patients were divided into two groups at random: one group received a placebo and the other group received aloe juice treatment. Sample size:, n = 25 patients with neck cancer. The treatment is Aloe Juice. (See the Excel File \"Chapter 13 Dataset\" to complete the questions below.) Variable Names: ID- Patient ID TRT- treatment group: 0 = placebo; 1 = aloe juice AGE- patient's age in years WEIGHTIN- patient's weight at the initial stage STAGE- initial cancer stage, coded 1 through 4 TOTALCIN- oral condition at the initial stage TOTALCW2- oral condition at the end of week 2 TOTALCW4- oral condition at the end of week 4 TOTALCW6- oral condition at the end of week 6 Research Question: Is there a difference in oral condition at the end of week 2 and at the end of week 4? In other words, we want to know if there is a difference between two related samples. (Assume the samples are not normally distributed.) 1. What type of test will we perform? We will perform the Wilcoxon Signed Rank Test 2. What is the parametric version of this type of test? (-1) Dependent samples t-test 3. List some of the pros and cons of using nonparametric tests. Pros: This test is more powerful in detecting significant results when distributional assumptions are violated; This is a good test to use when the data is not normally distributed; This test also analyzes the rank of data. Cons: This test does not analyze the actual raw data; This test is not as powerful as parametric tests when the assumptions are not met 4. List the assumptions for this type of analysis. The variables must be continuous The sample is random of a respective population The level of measurement is a least interval 5. Are the dependent variables a continuous measurement? Yes- the dependent variables are continuous measurements 6. Identify the null and alternative hypothesis. H 0 : The median of the difference between the oral conditions at the end of week two and week four is equal to zero H 1 : The median of the difference between the oral conditions at the end of week two and week four is not equal to zero Now, let's perform our analysis. Refer to the output below to answer the questions. Statistical Output Descriptive Statistics N 25 25 Std. Deviation 2.54 3.47 8.28 10.36 Minimum Maximum 4.00 6.00 16.00 17.00 N TOTALCW2 TOTALCW4 Mean Mean Rank Sum of Ranks 16 10.16 162.50 3 9.17 27.50 Ranks TOTALCW2 - TOTALCW4 Negative Ranks Positive Ranks Ties 6 Total 25 Test Statistics TOTALCW2 - TOTALCW4 Z -2.72 Asymp. Sig. (2 tailed) .006 7. According to the analysis, what are the medians for each group? Week 2: 8 Week 4: 10 8. Identify the appropriate test statistic and p-value for testing the claim that there is a difference in oral condition at the end of week 2 and week 4. Test statistic: -2.72 p-value: .006 9. Using the analysis, calculate the effect size. r= z N r= -0.544 10. Use APA style reporting to write up your results of this analysis. The oral conditions significantly changed after the aloe juice treatment at the end of week 4 (Mdn = 10) compared to aloe juice treatment at the end of week 2 (Mdn = 8), z = -2.72, p = . 006, r = -0.544