In Which of the Following Situations Would It Be Useful

Multiple Choice

In which of the following situations would it be useful to test for differences between two groups?

A) A retailer wishes to know if customer satisfaction is different between in-store v.online shoppers.
B) A beverage company wants to know if a new beverage concept differs between users v.nonusers of the current brand.
C) A department store wishes to know the differences between online catalogs vs.mail order catalog shoppers.
D) A state university ants to know is there is a significant difference in GPA between undergraduate and graduate students.
E) All of the above situations would benefit from tests for differences between two groups.