76 Find the appropriate values of n1 and n2 (assume that n1 = n2 ) needed to estimate (m1 - m2) with

a. A sampling error equal to 3.2 with 95% confidence.

From prior experience, it is known that s1  15 and s2  17.

b. A sampling error equal to 8 with 99% confidence. The range of each population is 60.

NW

c. A 90% confidence interval of width 1.0. Assume that s1 2  5.8 and s2 2  7.5.