posted by jig .
A researcher conducts a t test for dependent means in which it is predicted that there will be a decrease in unemployment from before to after a particular job-skills training program. The cutoff "t" needed is -1.8333. The standard deviation of the distribution of means of change scores is 2.0 and the mean change score for the sample studied is an increase of 5.2.
What is the effect size?
- 5.2/-1.833 = -2.84; large
- 2/5.2 = .38; approximately medium
- 5.2/2 = 2.60; large
- It can not be determined without also knowing the population standard deviation