Project Management Professional (PMP) Exam Practice – Question1465

Six sigma refers to the aim of setting tolerance limits at six standard deviations from the mean, whereas the normally expected deviation of a process is______________


A. One standard deviation
B. Two standard deviations
C. Three standard deviations
D. Undeterminable because of the unique nature of every process

Correct Answer: C

Explanation:

Explanation:
When the results of a sample of items measured falls within three standard deviations and that sample is representative of the entire population, you can assume that more than 99% of all items fall within that range. This generally accepted range of results has
been used by quality control professionals through the years. Six sigma is a program started by Motorola that, from a statistical standpoint, indicates a quality +standard of only 3.4 defects per million.