Dear Johan,
"the standard deviation is defined as the square root of the variance." while "The standard deviation has the same unit as the values you're measuring."
So we can say what's the unit of deviation? Is it the square of the unit of standard deviation?
I always think that the unit of deviation is the same to the values we're measuring. Maybe I make a mistake...
Thank you very much!
On 04/24/2012 10:30 AM, Johan Hattne wrote:
> Hi Qixu;
>
> This is by definition--the standard deviation is defined as the square root of the variance.
>
> http://mathworld.wolfram.com/StandardDeviation.html
>
> The standard deviation has the same unit as the values you're measuring, which makes its interpretation a tad easier.
>
> // Best wishes; Johan
>
>
> On 23 Apr 2012, at 18:13, Qixu Cai wrote:
>
>> Dear Ed,
>>
>> Why the variance is the square of standard deviation?
>>
>> thank you very much!
>>
>>
>> 在 2012年4月23日,20:53,Ed Pozharski<[log in to unmask]> 写道:
>>
>>> On Sun, 2012-04-22 at 12:47 +0530, Arka Chakraborty wrote:
>>>> baverage program in ccp4 gave average bfactor of 25.0 for the residue
>>>> but coot is showing 150!
>>> Variance is the square of standard deviation, thus var=150 means
>>> sigmaB~12 in that particular residue. High, but not impossible.
>>>
>>> --
>>> I don't know why the sacrifice thing didn't work.
>>> Science behind it seemed so solid.
>>> Julian, King of Lemurs
> Postdoctoral Fellow @ Physical Biosciences Division
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