z score in Excel

The z-score, also known as a standard score, is used in statistics. It measures the number of standard deviations of a specific number.

To calculate z-score you can use the following formula.

z-score = (x – μ) / σ

x – value

μ – mean

σ – standard deviation

Let’s take a look at the following example. This site iqtestprep.com shows the IQ score of famous people.

I chose just a few examples to illustrate how you can calculate the mean, standard deviation, and z-score.

You can copy the following example.

First Name	Last Name	IQ
Muhammad	Ali	78
Rowan	Atkinson	178
Kobe	Bryant	114
Warren	Buffet	145
Miley	Cyrus	120
David	Duchovny	147
Thomas	Edison	145
Jodie	Foster	132
Ariana	Grande	105
Stephen	Hawking	160
Charles	Manson	109
OJ	Simpson	89

Calculating standard deviation in Excel

1. Calculate the mean for the IQ scores, by using the following formula =AVERAGE(C2:C13) and call it mean.

2. Calculate the standard deviation with this formula: =STDEVPA(C2:C13) and call it stdev.
3. In cell D2, calculate the z-score for the first IQ: =STANDARDIZE(C2, mean, stdev).
4. Use autofill to calculate the remaining z-scores.

This is the result of our calculations.