In each of Exercises, we have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. In each case, do the following tasks. a.Determine the...

In each of Exercises, we have provided the numbers of successes and the sample sizes for independent simple random samples from two populations. In each case, do the following tasks.

a.Determine the sample proportions.
b.Decide whether using the two-proportions z-procedures is appropriate. If so, also do parts (c) and (d).
c.Use the two-proportions z-test to conduct the required hypothesis test.
d.Use the two-proportions z-interval procedure to find the specified confidence interval.

x1 = 18, n1 = 40, x2 = 30, n2 = 40; left-tailed test, a = 0.10; 80% confidence interval