Statistics Function on TI-89

A student currently taking physics asked me on AIM the other day how one would calculate the standard deviation of a set of numbers on their calculator. The function for standard deviation on a TI-89 is stdDev(), unlike excel which uses stdev(). You just have to input a set of numbers that's comma delimited and enclosed in braces. The function stdDev() among others is located in the statistics submenu of math (2nd+5), and braces can be entered with 2nd+( or 2nd+).



So if we have stdDev({0.9,1.0,1.1}), the calculator will return a value of .1. This is a lot easier than using the formula which is definately a nightmare. Oh sigma. Also located in the statistics submenu is the mean() function for calculating average and the median() function for finding the number in a set that separates the higher half from the lower half of numbers. Both functions work the same way as stdDev(), and are comma delimited.