# Statistics Question 3

Oct 25th, 2015
DreamIt
Category:
Statistics
Price: \$20 USD

Question description

From historical data you know that the time it takes to do a certain job is normally distributed with a mean of 130 minutes and a standard deviation of 20 minutes. To monitor performance, each week a sample of 25 jobs is selected and the average time it takes to do the job is recorded. In a particular week the average time to do the job was 128 minutes with a standard deviation of 16 minutes. The distribution of times in the sample comes out bell-shaped. What can you say, if anything, about each of the following intervals: (a) 128 ± 2 x 16, (b) 130 ± 2 x (20/√25), (c) 128 ± 2 x (16/√25), (d) 128 ± 2 x (20/√25).

(Top Tutor) Daniel C.
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School: Carnegie Mellon University

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