The following information is obtained from two independent samples selected from two normally distributed populations.
n1 = 18 1 = 7.82 σ1 = 2.35
n2 = 15 2 = 5.99 σ1 = 3.17
a. What is the point estimate of µ1 – µ2?
b. Construct a 99% confidence interval for µ1 – µ2. Find the margin of error for this estimate.