I have a question. Why does the TI-83 under estimate the standard dev. for a short list of numbers such as: 6, 7, 8, 9,? I get a sample dev. of 1.29, and a pop. dev. of 1.12, but hand calculated the sample dev. is 1.66. How can I improve the accuracy of the TI-83 when calculating stats.? Thanks, John