A researcher wants to carry out a hypothesis test involving the mean for a sample

Question

of n = 20. While the true value of the population standard deviation is unknown, the
researcher is reasonably sure that the population is normally distributed. Given this
information, which of the following statements would be correct?
A. The researcher should use the z-test because the population is assumed to be
normally distributed.
B. The t-test should be used because á and ì are unknown.
C. The t-test should be used because ó is unknown and the sample size is small.
D. The researcher should use the z-test because the sample size is less than 30.

Answer 1

How about C?