Finds the sample variance of a list.
variance(list,[freqlist])
Press:
- 2ND LIST to enter the LIST menu.
- LEFT to enter the MATH submenu.
- 8 to select variance(, or use arrows.
TI-83/84/+/SE
1 byte
The variance( command finds the sample variance of a list, a measure of the spread of a distribution. It takes a list of real numbers as a parameter. For example:
:Prompt L1
:Disp "VARIANCE OF L1",variance(L1
Advanced Uses
Frequency lists don't need to be whole numbers; your calculator can handle being told that one element of the list occurs 1/3 of a time, and another occurs 22.7 times. It can even handle a frequency of 0 - it will just ignore that element, as though it weren't there.
Formulas
The formula for variance used by this command is:
(1)This is the formula for sample variance. The formula for population variance, which this command does not use, varies slightly:
(2)If the population variance is required, just multiply the result of variance() by $1-1/N$.
With frequencies wi, the formula becomes
(3)where $\overline{x}$ is the mean with frequencies included.
Related Commands
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