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Standart deviation

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by 4meonly » Sun Feb 22, 2009 6:07 am
OA D
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Re: Standart deviation

by x2suresh » Sun Feb 22, 2009 6:38 am
4meonly wrote:OA D

standard deviation will not change if you add/subtract same number to list.

s-2,r-2, t-2
0 =s-s , r-s, t-s
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Re: Standart deviation

by Ossa » Mon Feb 23, 2009 4:03 pm
Just to clarify, Standard deviation is a measure of dispersion of points around a certain mean and that is why subtracting the same number from all values only shifts the mean but dispersion remains the same and so the standard deviation does not change.
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by welcome » Mon Feb 23, 2009 7:29 pm
x2suresh,
Can you please tell me, in your solution, how come

0 =s-s , r-s, t-s
is considered as

0,s-t,s-r ???

because for making then equal we need to multiply by -1, which will chnage SD.

Please someone help me in this concept.
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by x2suresh » Mon Feb 23, 2009 7:40 pm
welcome wrote:x2suresh,
Can you please tell me, in your solution, how come

0 =s-s , r-s, t-s
is considered as

0,s-t,s-r ???

because for making then equal we need to multiply by -1, which will chnage SD.

Please someone help me in this concept.

it won't make any difference.

distance between r and s = distance between s and t


Its like you are moving all dispersion points values from poistive teritory into negative terriotory, but S.D will be the same.
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by welcome » Mon Feb 23, 2009 7:46 pm
Thanks, x2suresh, That was a quick point to note for me.
Shubham.
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