# A normal distribution has a mean of 140 and a standard deviation of 40. How do you calculate the percentile rank of a score of 172?

##### 1 Answer

78.81%

#### Explanation:

The question requires z-scores.

The formula is:

Where

Or

This is a bit easier to remember :)

(SD=Standard Deviation)

Plug in the values:

Now you look up the probability that corresponds to the

The probability that corresponds to the

All you have to do now is multiply by