Question

What is the z-score of X, if n = 72, `mu= 137`, SD =25, and X =13?

Answer 1

z-score is `-42.087`

Explanation:

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

As `mu=137`, `sigma=25`, `n=72` and `x=13`

z-score is `(13-137)/(25/sqrt72)=((-124)*sqrt72)/25=-42.087`