Suppose we have the following five data values: 3.0, 3.1, 3.2, 3.3, 3.4. There is more that one way to get statistics on these data values using the TI89; Here is one easy way:
First, enter the data values into a data variable. To do this, press to start the Data/Matrix Editor. Press the right arrow to open the submenu, and select "3: New". (Note: If you have already created a data variable, you can reuse it by selecting "1: Current" or "2: Open".) 

Scroll down to the "Variable:" input box, and type a name for the data variable. I have named my data variable "temp". Note:
In any case, when you have typed the name, press . 

Type the values into the "c1" column. Press after each value. The screen shot at right shows the screen after the values "3.0, 3.1, 3.2, 3.3, and 3.4" have been entered. 

Press (F5: Calculate) to open the Calculate dialog. Select "OneVar" as the Calculation Type, and enter "c1" in the "x........" input box. Press . 

On the first line, is the mean of the data values. The fourth line, Sx, is the standard deviation. 
