standard deviation (1 Viewer)

dzth

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does anyone know how to do standard deviation without a casio calculator?
i have a sharp calculator and it doesnt have the MODE SD function on it..

it's a sharp el-531VH if i remember correctly..
or is there a manual method of doing standard deviation?
please teach me.. thank you!
 
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well the formula is √ { [∑(y-y')2]/(n-1)}

where y are the elements
y' is the mean
n= number of elements

manual method:

i'll use an example...

example: find mean and s.d. of 2, 3, 6, 10

mean = (2+3+6+9)/4 = 5

s.d.

calculate ∑(y-y')2
= (2-5)2 + (3-5)2 + (6-5)2 + (9-5)2
= 9 + 4 + 1 + 16
= 30

divide by (n-1) in this case its (4-1) = 3
so 30/3 = 10

now you've got the variance. take square root of all that and you've got the standard deviation. :)
 

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