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:

$Z=\frac{x-\mu}{\sigma}$

Rewrite the equation for σ:

$\sigma=\frac{x-\mu}{Z}$

Now, substitute value into the formula:

$\sigma=\frac{73-58}{1.25}=\frac{15}{1.25}=12$

Therefore, the standard deviation on the test is = 12

ANSWER:

12