A worker was observed for four cycles of a repetitive operation. The observed times for work elements are 11, 10, 8, and 11 seconds, respectively. What sample size is appropriate for estimating the time for this work element within + 3 percent of the True mean time with 95 percent confidence (z = 1.96)?
A) fewer than or equal to 70
B) greater than 70 but fewer than or equal to 75
C) greater than 75 but fewer than or equal to 80
D) greater than 80

Question

Quizplus · Accepted Answer

The sample size can be calculated using the formula n = (z * σ / E)^2, where σ is the standard deviation and E is the margin of error (3% of the mean). Calculating this gives a sample size greater than 80.

A Worker Was Observed for Four Cycles of a Repetitive