Question

The scores of a given test were normally distributed

with a mean of 82. If James received a 67 with a z-score of
-2.5, what is the standard deviation?

Answer 1

The standard deviation is 6

Explanation:

The scores of a given test were normally distributed with a mean of 82.

`\mu = 82`

James received a 67 with a z-score of -2.5

Z score = -2.5

`\bar{x}=67`

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

`-2.5=(67-82)/(\sigma)`

`\sigma = (67-82)/(-2.5)`

`\sigma =6`

Hence The standard deviation is 6