Posted by **Brenda** on Saturday, December 3, 2011 at 2:03pm.

Given the following information, 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.

Work Element

Standard Deviation (minutes)

Mean Observed Time (minutes)

1

0.20

1.10

2

0.10

0.80

3

0.15

0.90

4

0.10

1.00

(Round your answer to the nearest whole number, the tolerance is +/-1.)