James Desreumaux,VP of Human Resources of American First Banks (AFB),is reviewing the employee training programs of AFB banks. His staff randomly selected personnel files for 100 tellers in the Southeast Region and determined that their mean training time was 25 hours. Assume that the population standard deviation is 5 hours. The 92% confidence interval for the population mean of training times is ________.
A) 16.25 to 33.75
B) 24.30 to 25.71
C) 17.95 to 32.05
D) 24.12 to 25.88
E) 24.45 to 27.32

Question

Quizplus · Accepted Answer

The 92% confidence interval is calculated using the formula: mean ± Z*(σ/√n). Here, the mean is 25, σ is 5, n is 100, and Z for 92% confidence is approximately 1.75. This gives the interval 25 ± 1.75*(5/√100) = 25 ± 0.875, resulting in 24.12 to 25.88.