According to a survey by Topez Enterprises, a travel auditing company the avg error by travel agent is 128. suppose this figure was obtained from random sample of 41 travel agent & standard dervivation is 21. What is the point estimate of the national avg error for all travel agemt at 98% confidence interval
Z for .01 on each side is approximately 2.33.
98% = mean ± Z(SD/√n) = 128 ± (2.33)(21/√41)
I'll let you do the calculations.