Math help for Sigma and Var?

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Math help for Sigma and Var?

What is the formula for std. dev and var.? For eg, how would i calc the std. dev and var for a set of numbers, 1,2,3,4?

2006-09-07 22:50:57 · 3 answers · asked by Starguru 2 in Education & Reference ➔ Other - Education

3 answers

Go to this site.

You can't really type square roots

http://mathworld.wolfram.com/StandardDeviation.html

2006-09-07 22:54:10 · answer #1 · answered by Curious 2 · 0⤊ 0⤋

find the average of them
count them
find the distance of each from average.
Square it
sum them
divide by n

find square of it for varians.

But making a search in google will be a good idea for you.

2006-09-08 05:57:05 · answer #2 · answered by iyiogrenci 6 · 0⤊ 0⤋

var=sum((Xi-mean)^2) for i =1 to n
std=square of var

2006-09-08 05:58:45 · answer #3 · answered by Rachel 1 · 0⤊ 0⤋