We have given the number of successes and the sample size for a simple random sample from
a population. In each case, do the following.
a. Determine the sample proportion.
b. Decide whether using the one-proportion z-test is appropriate.
c. If appropriate, use the one-proportion z-test to perform the specified hypothesis test.
$$x=10, n=40, H_{0}: p=0.3, H_{\mathrm{a}}: p < 0.3, \alpha=0.05$$