statistics.bgwoodruff.com

The Standard Error of the Mean

Watch "Sample Size" in Action


Each frame of this animation shows the mean of 8 samples. Each frame shows a new set of 8 samples.

[Text continues below animation.]



Here is the IMPORTANT bit of information.


Standard Deviation and Standard Errror of the Mean (SEM)
Sample Size
Standard Deviation/Standard Error
Width of Green Bar (arbitrary units)
1
Population Standard Deviation =100
400
2
SEM = 100/ (sqrt(2) = 70.71
283
4 SEM = 100 / sqrt(4) = 50.00 200
8 SEM = 100 / sqrt(8) = 35.36 141
16 SEM = 100 / sqrtt(16) = 25.00 100
32 SEM = 100 / sqrt(32) = 17.68 72
64 SEM = 100 / sqrt(64) = 12.5 50
128 SEM = 100 / sqrt(128) = 8.84 35

For the hardcore

Click here to see an animation for the center 50% instead of the center 95%.


©2006 by Burrton Woodruff. All rights reserved. Modified 9/29/06