A Methods and Measurements Analyst Needs to Develop a Time

Multiple Choice

A methods and measurements analyst needs to develop a time standard for a certain task. In a preliminary study, he observed one of his workers perform this task five times, with the following results:

How many observations should be made if the analyst wants to be 99.74 percent confident that the maximum error in the observed time is 2 seconds? Assume that the standard deviation of the task time is 4 seconds.

A) 5
B) 6
C) 25
D) 36
E) 49