Exam 1

1. Metainformation

   Tag	Value
   file	Inferential_Statistics_uu-Effect-size-815-en_uu-Effect-size-815-en
   name	uu-Effect-size-815-en
   section	Inferential Statistics/Effect size
   type	schoice
   solution	FALSE, FALSE, TRUE, FALSE
   Type	Case
   Language	English
   Level	Statistical Literacy

   Question

   A study of the relationship between location of deployment (Iraq or Afghanistan) and depression of soldiers primarily examines only whether soldiers became depressed, yes or no. A $\chi^2$-test is performed and the variables were found, in a sample of 60 soldiers, not to be independent: $\chi^2(1, n = 60) = 5.88$, $p = .015$. What is the value of the effect size that should be reported here?

   
   
   1. FALSE: $0.015$
   2. FALSE: $0.098$
   3. TRUE: $0.313$
   4. FALSE: This cannot be determined because the cross table is not given.
   
   

   Solution

   Location is a dichotomous variable (Iraq/Afghanistan), as is depression (yes/no). To calculate the effect size in this case, the phi coefficient can be calculated:

   $\phi= \sqrt{\frac{\chi^2}{n}} = \sqrt{\frac {5.88}{60}} =0.313$

   
   
   1. $.015$ is $p$-value and not the effect size.
   2. Thist answer ($.098$) forgot to root.
   3. $\phi= \sqrt{\frac{\chi^2}{n}} = \sqrt{\frac {5.88}{60}} =0.313$
   4. This can indeed be determined. Location is a dichotomous variable (Iraq/Afghanistan), as is depression (yes/no). To calculate the effect size in this case, the phi coefficient can be calculated.