Consider the following hypothesis test:
$$
\begin{aligned}
& H_0: p=.20 \\
& H_{\mathrm{a}}=p+.20
\end{aligned}
$$
A sample of 400 provided a sample proportion $\tilde{p}=.175$.
a. Compute the value of the test statistic.
b. What is the $p$-value?
c. At $a=.05$, what is your conclusion?
d. What is the rejection rule using the critical value? What is your conclusion?