A job consists of two work elements, P and Q. Completion time (in minutes) of each work element was measured. A pilot study involved collecting a sample of 40 observations. The results of this pilot study are summarized in the table below.
|
Work element
|
Mean completion time (in minutes)
|
Standard deviation (in minutes)
|
|
P
|
1
|
0.50
|
|
Q
|
1
|
0.05
|
For the mean study, the minimum sample size for the sample mean time of any work element to be within 0.1 minutes of its true mean time with 95% confidence (corresponding standard normal value, Z0.025 = 1.96 is _____________