Question

The class average on a math test was 75.5 and the standard deviation was 4.2. What is the z-score for a test score of 81?

Answer 1

`z=1.31`

Explanation:

Given -

`barx=75.5`
`sigma=4.2`
`z=(x-barx)/sigma=(81-75.5)/4.2=5.5/4.2=1.31`