This week we spent some time covering standard defiance. It seems like it's overwhelming but it really is not. All you need to know is what each letter stands for and boom you are pretty much good to go baby! Anyway here it is.
The formula used for these problems is s^2 = ((∑(xi^2)) / (n)) - x̅ ^2
When you see the symbol ∑ it means the sum.
The symbol xi stands for the numbers.
x̅ stands for the mean of the numbers.
The letter n stands for the amout of numbers being used in the problem.
The easiest way to work with standard deviance is to set up two columns for xi and xi^2. You have to find each part before plugging into the formula and working the problem. Also the variance is written as s^2.
EXAMPLE TIME
Find the standard deviance of 1,2,3,4,5
First set up your chart
Xi-xi^2
1-1
2-4
3-9
4-16
5-25
n=5
Now plug into the formula.
S=square root of
--Sarah (:
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