A study is conducted to determine whether sunshine affects depression. Eight individuals are given a questionnaire measuring depression immediately following a run of 10 consecutive days when the sun shone for over 80% of the daylight hours. The same individuals have their depression measured immediately following 10 consecutive days without any sunshine. The following data are collected. The higher the score the greater the depression. Using the Wilcoxon signed ranks test to evaluate the data, with a = 0.05 2 tail , T crit = _________.
A) 2
B) 5
C) ±3
D) 3

Question

A study is conducted to determine whether sunshine affects depression. Eight individuals are given a questionnaire measuring depression immediately following a run of 10 consecutive days when the sun shone for over 80% of the daylight hours. The same individuals have their depression measured immediately following 10 consecutive days without any sunshine. The following data are collected. The higher the score the greater the depression.  Using the Wilcoxon signed ranks test to evaluate the data, with a = 0.05 2 tail , T crit = _________.
A) 2 
B) 5 
C) ±3 
D) 3

Quizplus · Accepted Answer

To find the T crit value for the Wilcoxon signed ranks test, we need to refer to a critical values table for the test statistic. Since we have a sample size of n = 8, we can use Table 2 in the appendix of most introductory statistics textbooks. Using a significance level of a = 0.05 and a two-tailed test, we find that the critical value for T is 3. Therefore, the answer is D.

A Study Is Conducted to Determine Whether Sunshine Affects Depression