Calculating Sample Size and Precision
Work Element
Standard Deviation (minutes)
Mean Observed Time (minutes)
1 0.60 2.40
2 0.20 1.50
3 1.10 3.85
4 0.85 2.55
5 0.40 1.60
6 0.50 2.50
Determine the sample size needed if the standard time estimate is to be within 5 percent of the true mean 99 percent of the time.