An accounting firm is planning for the next tax preparationseason. From last year's returns, the firm collects asystematic random sample of 100 filings. The 100 filingsshowed an average preparation time of 90 minutes with a standarddeviation of 140 minutes. What is the probability that the mean completion time will bemore than 120 minutes? A. Approximately zero B. 0.0832 C. 0.4168 D. 0.0162 An accounting firm is planning for the next tax preparationseason. From last year's returns, the firm collects asystematic random sample of 100 filings. The 100 filingsshowed an average preparation time of 90 minutes with a standarddeviation of 140 minutes. What is the probability that the mean completion time will bemore than 120 minutes? A. Approximately zero B. 0.0832 C. 0.4168 D. 0.0162
Explanation / Answer
z = (120-90)/(140/(100)) = 2.14 ==> P(z< 2.14) =0.9838 P(z>2.14) = 1-0.9838= 0.0162 ==> ANSWER IS D