Mean and Standard Deviation on a Basic Scientific Calculator

About Modes | Entering Data | Calculating | Summary | Self-test

Note: This page is NOT relevant for graphing calculators like the TI-81, TI-82, TI-83, or TI-85.

Here's how to compute some basic statistics on a basic scientific calculator:


First, figure out if your calculator requires you to set it in "STAT MODE". The SHARP-brand calculators I've seen do, and some of the TI calculators do too. Look to see if you have a MODE button. The T.I.'s with a "STAT 1" button require this also.

Entering Data:

You may need to clear out old data first. Look for a [CA] button (on Sharps) or [CSR] (for clear statistics registers) on TIs.

Once you have set the mode (if needed), enter data as described in the next paragraph. If you aren't sure about needing to set the mode, see if the following works without setting a mode.

One at a time, type a number in your list of data, and then press the data-entry button. On the TI calculators, the data-entry button looks like this: [Capital Sigma+]. On the Sharp calculators, the data-entry button may have [M+] on it, or it might say "DATA".

So for example, if your list was 3,5,4,7,1, then on the TI, you would type 3[+]5[+]4[+]7[+]1[+].

On the Sharp, you would type 3[M+]5[M+]4[M+]7[M+]1[M+].

On both calculators, each time you enter a datum (unit of data), the calculator shows the count of the data entered so far. So if you've done the keystrokes above, your calculator should show "5" (or maybe "n=5"). You have now successfully entered your data.

Making calculations:

This part is easy. Once you have entered your data, to find the mean or average, find an   button and press it. The mean is displayed.

To find the standard deviation, find a button marked [x] or [n] or [xn] or just []. Press that and the standard deviation is displayed.

Watch out, don't press [y] or [n-1] or [xn-1] or just [s]. These are related to the standard deviation, but they aren't what we want.

Short summary:

Enter STAT mode if your calculator requires it. Clear the any old data if necessary. Enter the data one at a time using a [+] or [M+] button. Press an   button to get the average or mean, press [x] to get the S.D. (make sure you use the correct [] button for your calculator.

Test yourself:

Try to get the mean and standard deviation of   37.75, 38, 37, 38.5, and 37.5. You should get a mean of 37.75 and a standard deviation of 0.5.

Last Modified January 31, 2000.
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