3. Independent random samples of n 550 1 and n 560 2 observations were selected from populations 1 and 2, respectively. The sample sizes and computed sample statistics are given in the table:

a. Find a 90% confidence interval for the difference in population means and interpret the interval.

b. Suppose you wish to estimate (m 2m ) 1 2 correct to within .2, with probability equal to .95. If you plan to use equal sample sizes, how large should n1 and n2 be?

Transcribed Image Text:

Population 1 2 Sample Size 50 60 Sample Mean 100.4 96.2 Sample Standard Deviation 0.8 1.3