Question

9) Statistical information for a data set is given. • The mean is 18.1. • The Z-score for 13.0 is -1.7. What is the standard deviation for this data set? A 1.7 B 3.0 C 3.4 D 5.1

Answer 1

The Solution.

Step 1:

We shall state the formula for Z-statistics.

Step 2:

We shall substitute the above values into the formula.

`\begin{gathered} -1.7=(13.0-18.1)/(\sigma) \\ \text{Cross multi\lbrack{}plying, we get} \\ -1.7\sigma=-5.1 \\ \text{Dividing both sides by -1.7, we get} \\ \sigma=(-5.1)/(-1.7)=3.0 \end{gathered}`

Step 3:

Presentation of the Answer.

Thus, the correct answer is 3.0 (option B)