Do It Yourself!: Why Divide by n - 1?
Sample Size = 3
Click on the "New Sample" button several times to see what is happening. A sample is drawn from a population with standard deviation of sigma = 29.2. The applet then calculates two different sample standard deviations -- one dividing by n and one dividing by n-1. Then speed up the process by clicking on the "10 Samples" or "100 Samples" buttons. Does dividing by n or n - 1 produce sample standard deviation that are on average closer to the true value of 29.2?
Sample Size = 10
Follow the same instructions as above. With a larger sample, does it make as much difference whether you divide by n or n - 1 when computing the sample standard deviation? Click your browser's Refresh or Reload button to reset and start with new samples.
Return to the index of applets
The applet(s) on this page is from Seeing Statistics,™ an online, interactive statistics textbook. Seeing Statistics is a registered service mark used herein under license. The applet(s) on this page was designed to be used exclusively with Introduction to Probability and Statistics, Eleventh Edition, by Mendenhall, Beaver, & Beaver. (c) 2003, Duxbury Thomson Learning. The applet(s) on this page may not be copied, duplicated, or reproduced for any reason.