x = 8, n = 40, 95% level.
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 tasks.
a. Determine the sample proportion.
b. Decide whether using the one-proportion z-interval procedure is appropriate.
c. If appropriate, use the one-proportion z-interval procedure to find the confidence interval at the specified confidence level.