Question

What is the z-score of sample X, if `n = 36, mu= 12.3, St. Dev. =21, and mu_X =18.5`?

Answer 1

`z=1.77`

Explanation:

`z=(mu-mu_x)/(SE)`
`SE=sigma/sqrt n=21/sqrt36=21/6=3.5`
`z=(12.3-18.5)/3.5=(-6.2)/3.5=-1.77`