Chapter 2.1, Problem 35E

To determine

To find: the actual ACT score

Answer to Problem 35E

18

Explanation of Solution

Given:

Mean = 21

Standard Deviation =5

Standardized score is $\text{Z}$ = -0.6

Formula used:

  $\text{Z=}\frac{x-\mu }{\sigma }$

Calculation:

  $\begin{array}{l}\text{Z=}\frac{x-\mu }{\sigma }\\ Z\times \sigma \text{= }x-\mu \\ Z\times \sigma \text{ + }\mu \text{ = }x\\ x=\mu \text{+ }Z\times \sigma \\ x=21+\left(-0.6\right)\times 5\\ x=21-3\\ x=18\end{array}$

Hence, the correct option is (d)