Question

A teacher tells a class that the mean raw score on a test was 58. Alex has a raw score of 73 and a z-score of 1.25. What was the standard deviation on the test? (Round to the nearest tenth)

Answer 1

Given:

Mean raw score(population mean), μ = 58

z-score, Z = 1.25

Raw score, x = 73

To find the standard deviation, σ, use the Z-score formula below:

`Z=(x-\mu)/(\sigma)`

Rewrite the equation for σ:

`\sigma=(x-\mu)/(Z)`

Now, substitute value into the formula:

`\sigma=(73-58)/(1.25)=(15)/(1.25)=12`

Therefore, the standard deviation on the test is = 12

ANSWER:

12