Which of the following is not a valid description of an outl

Which of the following is not a valid description of an outlier?

a) A data value several standard deviations from the mean.

b) A data value that lies below Q₁ or above Q₃

c) A data value that is very unusual

d) A data value beyond the outer fences

Solution

(B) is not a valid description because by definition 25% data lies below Q1, and 25% lies above Q3, making total of 50% data being categorized as outlier