Which of the Following Statements Is Most Nearly Correct, Other

Multiple Choice

Which of the following statements is most nearly correct, other things being equal?

A) Using Student's t instead of z makes a confidence interval narrower.
B) The table values of z and t are about the same when the mean is large.
C) For a given confidence level, the z value is always smaller than the t value.
D) Student's t is rarely used, because it is more conservative to use z.