Find the appropriate values of n1 and n2 (assume n1 = n2) needed to estimate (1 -

Question:

Find the appropriate values of n1 and n2 (assume n1 = n2) needed to estimate (µ1 - µ2) for each of the following situations:
a. A margin of error equal to 3.2 with 95% confidence. From prior experience it is known that σ1 ≈ 15 and σ2 ≈ 17.
b. A margin of error equal to 8 with 99% confidence. The range of each population is 60.
c. A 90% confidence interval of width 1.0. Assume that σ21 ≈ 5.8 and σ22 ≈ 7.5.