**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 *s**x*, the minimum is *minX*, the 1^{st} quartile
is *Q1*, the median is *Med*, the 3^{rd} 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 *s**x*, the population standard deviation,
for every list of numbers. Unfortunately, *s**x* 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 *s**x*. 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, *s**x* will have a value next to it and Sx will have nothing next to it. When in doubt, use *Sx* and not *s**x* .