Use the Data Given Below to Answer the Following Question(s) $\frac { \hat{p} - \pi _0 } { \pi ( 1 - \pi_ 0 ) / n }$

Multiple Choice

Use the data given below to answer the following question(s) .
In a lower one-tailed hypothesis test, chosen level of significance = 0.10, true mean = 30, sample size = 55, and t-test statistic = -1.76.
-Which of the following computes the test statistic for a one-sample test for proportions?

A) z = $\frac { \hat{p} - \pi _0 } { \pi ( 1 - \pi_ 0 ) / n }$

B) z = $\frac { \hat{p} - \pi _0 } { \pi / n }$

C) z = $\frac { \hat{p} - \pi _ { 0 } } { \sqrt { \pi \left( 1 - \pi _ { 0 } \right) / n } }$

D) z = $\frac{\hat{p}-\pi _0}{\sqrt{\pi(1-\pi_ 0) ^{2} / n}}$