Robert B. answered • 05/13/14
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Variance
The Variance is defined as:
The average of the squared differences from the Mean(average).
The Variance is defined as:
The average of the squared differences from the Mean(average).
1st step find the MEAN:
(10+9+9+8+8+8+8+6)/8 = 8.25
2nd step: calculate the Variance (σ2)
Ttake each difference, square it, and then average the result:
The variance will be 1.1875 if you do the math properly.
The variance will be 1.1875 if you do the math properly.
If they ask you to do the standard deviation, just take the square root of the above answer.
The square root of variance is sd, so take the square root of the above answer and you will get σ (sigma or standard deviation)
Robert B.
Actually it depends on the question...
Please refer to the following link
http://nebula.deanza.edu/~bloom/math10/m10divideby_nminus1.pdf
Sometimes you might need to divide by n-1 which would be 7, not 8 as shown in the above link
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05/13/14
Dana W.
05/13/14