Question

If the mean I.Q. is 100 and the standard deviation of I.Q. scores is 15, then an I.Q. of 130 will have a z score (or standard score) of ___________________.

Answer 1

Answer: I.Q. of 130 will have a z score (or standard score) of 2.

Step-by-step explanation:

Let X be a random variable that represents the  I.Q. score.

Formula for Z-score : $Z=\dfrac{X-mean}{standard \ deviation}$

As per given, mean I.Q. = 100 and the standard deviation =15

For X = 130,

$Z=\dfrac{130-100}{15}=\dfrac{30}{15}=2$

So, I.Q. of 130 will have a z score (or standard score) of 2.