Question

In making the decision to return to school for an MBA, prospective students desire to know the time it will take to recoup their investment (forgone wages plus tuition and other direct costs). The time it will take to recoup their investment is normally distributed. You are in charge of estimating this time for a brochure advertising an MBA program at UCLA. You randomly sample 20 past UCLA MBA students and find that the sample average is 3.61 years with a standard deviation of 0.63 years. To estimate the mean number of years required to recoup an investment in a UCLA MBA to within 2 months (0.17 years) with 80% confidence, the sample size should be approximately

75.

38.

53.

23.

none of the above.

Answer 1

Answer)

We need to use standard normal z table to solve the problem

Critical value z from z table for 80% confidence level is 1.28

Margin of error (MOE) = t*s.d/√n

0.17 = 1.28*0.63/√n

N = 23