Question

In a certain normal distribution of scores, the mean is 30 and the standard deviation is 3. Find the z-score corresponding to a score of 23. a. 10.00 c. 7.7 b. 2.33 d. –2.33 Please select the best answer from the choices provided A B C D

Answer 1

d. –2.33

Explanation:

The z-score can be calcualted with the following formula

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

Where
`\mu` is the mean and
`\sigma` is the standard deviation.

So, in this problem, we have the following data

`x=23\\\mu =30\\\sigma=3`

Replacing all values in the formula, we have

`Z=(23-30)/(3)=(-7)/(3) \approx -2.33`

Therefore, the right answer is d.