1. Enter the data; after each value, press the "data
entry" key. This is the key which shows the summation symbol, which looks
roughly like this:
-------
\ +
\
/
/
-------
For example, to enter the values 2,5,1 press: 2, data entry key, 5, data entry key, 1, data entry key.
2. For the mean, type [2nd], [x2]. (In this example, you should obtain the result 2.66...) For the standard deviation, use [2nd], [square root key]. The variance is obtained by squaring the standard deviation.
(Note: The TI-30 can also calculate the standard deviation using n instead of n-1, but we do not use that option.)