Re: 回复: [chrony-users ] question about the values in critical_runs array

Miroslav Lichvar <[email protected]> Thu, 18 Jul 2024 15:04:09 +0200
Newsgroups gmane.comp.time.chrony.user
Message-ID <ZpkSyS_DG_TQRnSj@localhost>
On Tue, Jul 09, 2024 at 11:34:04AM +0000, 邹林志08963 wrote:
> I found a formula on the web:
> 
>       Z = [ r - E(r) ] / sigma
> 
>       E(r) = ( 2 * n1 * n2 ) / ( n1 + n2 ) + 1,
> 
>       sigma = sqrt{ [ 2 * n1 * n2 * (  2 * n1 * n2 - n1 - n2 ) ] / [ ( n1 + n2 ) *  ( n1 + n2 ) * ( n1 + n2 -1 ) ] }
> 
> if Z is z ,  r is runs , E(r) is mu ,  sigma is sqrt(var),   then r = Z * sigma + E(r).
> 
> should  runs be   "mu + sqrt(var)"  or  "mu -sqrt(var)" ?

I'm not sure what exactly you are pointing out here, but in our case
we care only about the lower bound to increase the number of runs when
it's lower than expected for the number of samples. If the number of
runs is too high, we don't care.

-- 
Miroslav Lichvar


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