# Mean and Standard Deviation on a TI-86

Here's how to compute some basic statistics on your TI-86:
1. Press the [2nd][STAT] button. You should see something like this on your screen:
2. Press the [CALC] button (that is, press the button on your calculator below the box labeled "CALC" on the screen). Now your screen should look something like:
3. Press [OneVa] to indicate that you want to CALCulate OneVariable statistics. You should now see:
4. Now to tell the calculator the list of numbers for which you want to compute those statistics, press [2nd][LIST] to get:
and use the braces now visible in the menu to type {1,2,2,3,3,3,5,7} (or whatever your actual list is):
5. When you press [ENTER], many statistics will appear:The =3.25 tells you the average of your list, and the x=1.785... tells you the standard deviation of your list. If you scroll down, you will see n=8, telling you there are 8 data items, a good check of your typing.

### Short summary:

• To compute the mean and standard deviation of a list, say {1,3,6,6,10}, type OneVar {1,3,6,6,10}
• Get OneVa(r) on the [2nd][STAT][CALC] menu.
• Get the braces "{" and "}" from the [2nd][LIST] menu.
• and x are the mean and standard deviation, respectively. n is the number of data items entered.

### 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.

## Bonus Topics:

### Frequency tables:

If you have many repeated data items, such as a frequency table:

 data item frequency 3 4 8 5 1 7 5 1

...meaning that your list contains four 3's, five 8's, etc., then you need not type all the repeated data, but can input frequencies directly as shown below. The first list entries are the data items, the second list entries are the respective frequencies. Don't forget the COMMA between the two lists, or your results will be completely wrong.

When you press [ENTER], you get  and scrolling down shows which confirms (with n=17) that we have really entered 17 data items.

### Help with medians and other bonuses:

After computing OneVariable statistics for a particular list, scroll down a little farther and see what nice surprises await you.