Which of the Following Is the Test Statistic for a One-Sample

Multiple Choice

Which of the following is the test statistic for a one-sample test for mean when the population standard deviation is unknown?

A) $t=\frac{\bar{x}-\mu 0}{s / \sqrt{n}}$

B) $z=\frac{s / \sqrt{n}}{\bar{x}-\mu_{0}}$

C) $z=\frac{\bar{x}-\mu_{0}}{\sigma / \sqrt{n}}$

D) $t=\frac{\sigma / \sqrt{n}}{\bar{x}-\mu 0}$