Help me with a question for school please?

Question

When the population standard deviations are unknown and the sample sizes are large, the ________ test can be used, but if the sample sizes are small, the _______ test must be used to compare population means.

a. t, Z

b. t, F

c. F, t

d. Z, t

Answer 1

d.

When the population standard deviations are unknown and the sample sizes are large, the "Z" test can be used, but if the sample sizes are small, the "t" test must be used to compare population means.