8.28 To increase the fertility of his crops, a maize farmer adds two types of fertilizers, A and B, to two different areas of his farmland. He selects a random sample of 11 ears of maize planted using fertilizer A and finds that they have an average length of 6.5 inches with a sample standard deviation of 0.45 inches.

Concurrently, he selects a random sample of 12 ears of maize planted using fertilizer B, which have an average length of 7.2 inches with a sample standard deviation of 1.02 inches. Assume that the two population distributions are normal and have the same variance. Find a 95% confidence interval estimate for the difference between the population mean length of an ear of maize planted using fertilizer A and for those planted using fertilizer B.