A firm using a 3-sigma statistical quality control program would expect to find an average of how many defects per million samples?
A) 3 times the standard deviation of the number of defects
B) 6 times the mean number of defects
C) 3
D) 2,700

Question

Quizplus · Accepted Answer

A 3-sigma statistical quality control program is designed to identify defects that are three standard deviations away from the mean. This means that 99.73% of all samples will fall within three standard deviations of the mean, leaving only 0.27% of all samples outside of this range. In terms of defects, this translates to an expected average of 2,700 defects per million samples (0.27% of a million). Therefore, the correct answer is D.

A Firm Using a 3-Sigma Statistical Quality Control Program Would