Calculating Sample Standard Deviations

TI-30XA

• turn the calculator off then back on to clear any prior data (other model calculators may require pressing a separate stat clear key).
• type the number for the first observation, then press the Σ+ (pronounced Sigma plus) key.  The display will change to n=1, indicating that one number has been stored in statistics memory.
• repeat for additional observations.  Example:  type 14, 12, 15, and 13, pressing Σ+ after each.  The display should now read n=4.
• press the yellow 2nd key, then press the σxn-1 key (which is the 2nd function of the square root key on this calculator).  For the above example, the answer should be 1.29 to two decimals.  Other statistics can be found by pressing the respective keys.

TI BA II Plus

• press 2nd, 7 (Data)
• press 2nd CE/C to clear the worksheet
• enter data into the X fields (X01, X02, etc.).  To do so, begin by typing the first observation and press Enter
• press the down arrow twice, then type the second observation and press Enter.  Repeat  until all observations have been entered.  Example:  14, 12, 15, 13
• press 2nd, 8 (Stat)
• press 2nd, Set.  Repeat until the screen reads 1-V
• press the down arrow repeatedly to display statistics one at a time.  The sample standard deviation is found in Sx after the third time the down arrow is pressed.  For the above example, the answer should be 1.29 to two decimals.

TI 83 and 84

• press Stat, then Edit
• if list L1 is not empty, clear it.  Make sure all rows are blank, not containing zero.  If not, clear the list:
• use arrow to select list L1, then press Clear, then Enter
• put the observations in L1, pressing Enter after each.  Example:  14, 12, 15, 13
• press 2nd, Quit
• press Stat, Calc, 1-Var Stats, Enter
• if you have more than one list with data, press 2nd, List, then select L1 and press Enter.
• a list of statistics is displayed.  The sample standard deviation is in Sx.  For the above example, the answer should be 1.29 to two decimals.