For each description below, indicate which t test would be most appropriate for analyzing the data: ·         A researcher matches two groups of subjects on their average GPA. Then the groups are...

For each description below, indicate which t test would be most appropriate for analyzing the data:

·         A researcher matches two groups of subjects on their average GPA. Then the groups are compared on their memory scores after studying a list of words. Group 1 sleeps for 8 hours after study, and Group 2 stays awake for 8 hours after study.

·         Subjects are randomly assigned to either a treatment group or a control group. Their scores on a depression questionnaire are then compared.

·         An ACT practice class compares the mean scores on the test for students who took the class with the known mean of 18 on the test for all students who took the test that year.

·         Subjects are tested on time to complete a Sudoku puzzle both with and without caffeine.