x1 = 20, s1 = 4, n1 = 30, x2 = 18, s2 = 5, n2 = 40
a. Right-tailed test, α = 0.05
b. 90% confidence interval
We have provided summary statistics for independent simple random samples from two populations. In each case, use the pooled t-test and the pooled t interval procedure to conduct the required hypothesis test and obtain the specified confidence interval.