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Question 7.1: Determining Number of Observations Needed in a time Study A ...

Determining Number of Observations Needed in a time Study

A time study analyst wants to estimate the time required to perform a certain job. A preliminary study yielded a mean of 6.4 minutes and a standard deviation of 2.1 minutes. The desired confidence is 95 percent. How many observations will he need (including those already taken) if the desired maximum error is:

a. ± 10 percent of the sample mean?

b. One-half minute?

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