A value of x in a sample is said to be unusual if A x2s

A value of x in a sample is said to be unusual if

A x-2s<x<x+2s

B x<x-2s OR x>x+2s

C x>x+s

D x<x

Solution

In statistics we call a value as Unusual or Outlier if the value fails to lie within the confidence band. Now let X₁......X_n be a sample pf size n from a population. Now we say a value is unusual if that value lies outside the confidence band, i.e the inteval (x bar-2*s, x bar+2*s) where x bar is the sample mean and s is the sample standard deviation. So x will be unusual if x < x bar-2*s OR x > x bar +2*s.

option (b) is true.