Question

The mean of a set of credit scores is 690 and 14. Which credit score is within a z-score of 3.3?
634
640
720
750

Answer 1

The answer is c) 720.

Answer 2

Answer:

C. 720.

Step-by-step explanation:

We have been given that the mean of a set of credit scores is 690 and standard deviation is 14.

To find the credit score that is within a z-score of 3.3 we will use z-score formula.

$z=\frac{x-\mu}{\sigma}$, where,

$z=\text{z-score}$,

$x=\text{Raw score}$,

$\mu=\text{Mean}$,

$\sigma=\text{Standard deviation}$.

Upon substituting our given values in above formula we will get,

$3.3=\frac{x-690}{14}$

Let us multiply both sides of our equation by 14.

$3.3*14=\frac{x-690}{14}*14$

$46.2=x-690$

Let us add 690 to both sides of our equation.

$46.2+690=x-690+690$

$736.2=x$

Upon looking at our given values we can see that credit score 720 is within a z-score of 3.3, while 750 is above our given z-score, therefore, option C is the correct choice.