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 for famous people.

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

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

This is the result of our calculations.