Question

A sociologist wants to know about the stress levels in the nation over the past years. In the late 1990s, the average score on the Brown's Stress Inventory (BSI) in the nation was 18 with a variance of 51.84. A current day sample of 21 produces a mean BSI score of 18.5. What can the sociologist concludes with an α of 0.01?

a) What is the appropriate test statistic?
---Select--- na z-test one-sample t-test independent-samples t-test related-samples t-test

b)
Population:
---Select--- the nation the years stress levels current sample the BSI score
Sample:
---Select--- the nation the years stress levels current sample the BSI score

c) Compute the appropriate test statistic(s) to make a decision about H₀.
(Hint: Make sure to write down the null and alternative hypotheses to help solve the problem.)
critical value =  ; test statistic =  
Decision:  ---Select--- Reject H0 Fail to reject H0

d) If appropriate, compute the CI. If not appropriate, input "na" for both spaces below.
[  ,  ]

e) Compute the corresponding effect size(s) and indicate magnitude(s).
If not appropriate, input and select "na" below.
d =  ;   ---Select--- na trivial effect small effect medium effect large effect
r² =  ;   ---Select--- na trivial effect small effect medium effect large effect

f) Make an interpretation based on the results.

There has been a significant increase in depression over the years.There has been a significant decrease in depression over the years.    There has been no significant change in depression over the years.

Answer 1