Variations that fall more than three standard deviations from the mean are attributed to assignable cause.

Question

Quizplus · Accepted Answer

This statement is true. Variations that fall more than three standard deviations from the mean are considered highly unlikely to occur by chance and are therefore likely to be caused by a specific, assignable cause. This is why they are referred to as "outliers" and should be investigated for possible sources of variation.

Variations That Fall More Than Three Standard Deviations from the Mean