A Methods and Measurements Analyst for Timepiece, Inc How Many Observations Should Be Made If He Wants to Develop

Multiple Choice

A methods and measurements analyst for Timepiece, Inc., needs to develop a time standard for the task of attaching a watch to a wristband. In a preliminary study, he observed one of his workers perform this task five times, with the following results: $$\begin{array} { | l | c | c | c | c | c | } \hline \text { Observation } & 1 & 2 & 3 & 4 & 5 \\\hline \text { Time(Seconds) } & 27 & 19 & 20 & 21 & 13 \\\hline\end{array}$$ How many observations should be made if he wants to be 95.44 percent confident that the maximum error in the observed time is one second? Assume that the standard deviation of the task time is five seconds.

A)  5
B)  10
C)  25
D)  100
E)  121