The standard error of mean, or SEM, is a common statistical measurement. It’s easy to find with a spreadsheet. Let’s learn how to find SEM in Microsoft Excel.
How to Find SEM in Microsoft Excel
SEM helps measure the accuracy of sample means. It’s a useful value if you have a table of sample data, for example. Consider this data set. It’s a list of scores, and you want to find the SEM for the data.
SEM is found by dividing the sample standard deviation by the square root of the count of samples. This isn’t a function that Excel has built-in, so you’ll need to build a quick formula.
Find an empty cell, and click into it. Start your formula by typing =. Now it’s time to add the first part of the function, which is the numerator of the SEM formula.
Continue by typing STDEV.S, which tells Excel to find the standard deviation of a sample. Continue with (, then click and drag to select your sample, which is the numerical data range from the table.
Close with ), then type / to begin the denominator of your function. This is where you’ll add the formula for the square root of the sample count.
Type SQRT(. From here, you have two options. If you know how many samples you have – in this case, 5 – simply type (5). But if you have a larger data set, it’s helpful to have Excel count the samples for you.
With that in mind, we’ll have Excel count. Continue by typing COUNT(, then select your data range, and conclude with )).
Your full formula should read:
=STDEV.S(B2:B6)/SQRT(COUNT(B2:B6))
Hit Enter, and Excel returns the standard error of your mean (SEM).
It’s easy to see how Excel makes statistics a breeze, thanks to built-in functions and formulas.
Square in Excel