Basic Statistics for a List of Numbers

Brief Instructions

Press STAT and ENTER. Highlight L1 and press CLEAR and ENTER. Enter your data values under L1.

TI-83's and Older TI-84's: Press STAT, choose CALC and press ENTER twice.

Newer TI-84's:Press STAT, choose CALC and press ENTER once. The calculator display will look something like the following.

 1-VarStats Freq: L1 FreqList: Calculate

Make sure L1 is next to Freq: and there is nothing next to FreqList:. Then highlight Calculate and press ENTER.

The mean is , the sample standard deviation is Sx , the population standard deviation is sx, the minimum is minX, the 1st quartile is Q1, the median is Med, the 3rd quartile is Q3, and the maximum is maxX.

Detailed Instructions

We will use the following list of numbers for this example: 5.1, 2.3, 5.7, 8.1, 4.6, 8.7, 6.5, 7.2, 5.7.

Press the STAT button and the ENTER button. Highlight L1 and press CLEAR and ENTER. Enter the list of numbers given above under L1. For instructions on how to do this, see Entering Data.

TI-83's and Older TI-84's: Once the numbers are all entered, press the STAT button again and move the cursor to CALC (short for CALCULATE) and press the ENTER button twice.

Newer TI 84's: Once the numbers are all entered, press the STAT button again and move the cursor to CALC (short for CALCULATE) and press the ENTER button once. Your calculator display should look like the following.

 1-VarStats List: L1 FreqList: Calculate

Make sure L1 is next to List:. You obtain L1 by pressing 2nd and 1. If anything is next to Freq:, put the cursor on this thing, and press the delete key, DEL.

For any of the TI-83 or TI-84 calculators, the display should look like the column below on the left. To see the display beyond n = 9, just press the down-arrow key a few times. The terms on the right give the English meanings for the statistical abbreviations on the left. The calculator computes some of these numbers to nine decimal place accuracy just because it can. However, since the original data had only one place accuracy, you should round estimates for the mean and standard deviation to two decimal places.

Also note that the calculator computes a value for sx, the population standard deviation, for every list of numbers. Unfortunately, sx is only meaningful when the list of numbers constitutes data from each and every member of the population. Usually, you do not have data from the entire population and in this case you need to use the sample standard deviation Sx instead of the population standard deviation sx. About the only time we will use the population standard deviation is when we are finding the mean and standard deviation of a probability distribution. In this case, sx will have a value next to it and Sx will have nothing next to it. When in doubt, use Sx and not sx .