# Mean and Standard Deviation on a Basic Scientific Calculator

### Note: This page is NOT relevant for graphing calculators like the TI-81, TI-82, TI-83, or TI-85.  They have their own help pages on my site.

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

### Background:

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.
IF YOU HAVE A MODE-BASED calculator, as described above:
Figure out how to get stat mode.
• On the Sharp calculators, try [MODE][1]. Look for a tiny word "STAT" displayed on your screen. If [1] doesn't work, try other numbers. As an absolutely last resort (I'm joking), look in your calculator manual under "statistics".
• On newer Sharp calculators, after [MODE][1] you may see and additional menu.  On mine, the option 0:SD is the one you want to press next.
• On the TI calculators, try either [MODE][STAT]or [2nd][STAT 1] or [3rd][STAT 1] until a tiny "STAT" is displayed on your screen.

### 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: [+]. On the Sharp calculators, the data-entry button may have [M+] on it.  Newer Sharps have a [DATA] button; you may need to press a shift key to get there.  Use the "DATA" key if you have it.

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 a newer Sharp, you would type 3[DATA]5[DATA]4[DATA]7[DATA]1[DATA].
On an older Sharp w/o the "DATA" button, 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" or even "DATA SET=  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+]or [DATA] 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.