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.
[tex]z=\frac{x-\mu}{\sigma}[/tex], where,
[tex]z=\text{z-score}[/tex],
[tex]x=\text{Raw score}[/tex],
[tex]\mu=\text{Mean}[/tex],
[tex]\sigma=\text{Standard deviation}[/tex].
Upon substituting our given values in above formula we will get,
[tex]3.3=\frac{x-690}{14}[/tex]
Let us multiply both sides of our equation by 14.
[tex]3.3*14=\frac{x-690}{14}*14[/tex]
[tex]46.2=x-690[/tex]
Let us add 690 to both sides of our equation.
[tex]46.2+690=x-690+690[/tex]
[tex]736.2=x[/tex]
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.
