Question

What is the z-score of X, if n = 20, `mu= 20`, SD =3, and X =31?

Answer 1

z-score is `16.4`

Explanation:

z-score of variable `x` with mean `mu`, and standard deviation `sigma` is given by `(x-mu)/(sigma/sqrtn)`

As `mu=20`, `sigma=3`, `n=20` and `x=31`

z-score is `(31-20)/(3/sqrt20)=(11*sqrt20)/3=16.4`