
Re: FALSIFICATION
Posted:
Jun 13, 2007 12:59 PM


> Followup, in SHORT, the continuity correction leads > to better results: > ______With C.C._____EXACT_______Without C.C. > ______0.00144______0.00156________0.00212____ > Diff___0.00012_____________________0.00056____
I was correcting your arithmetic. The actual result with CC is 0.00306, leading to a difference of 0.003060.00156 = 0.00150, which is even worse than the 0.00056 error without the CC.
> > *************** > See my post Jun 13, 2007, 7:29 AM. And APPRECIATE > that Jack Tomsky DID FALSIFY my evaluation > > I WROTE (ipsis verbis, please check): > Date: Jun 13, 2007 7:29 AM > Author: Luis A. Afonso > Subject: Re: Help with probability&stat problem > > EXACT : p(X<=10) = 0.00156 > Normal Approximation > *** Without C.C. > Z = (10  22)/sqrt(0.2*0.8*110) = 22/ 4.1952 = > 2.8604. > ________________ F(Z) = 0.00212 > *** With C.C. > ________Z = (10  22 + 0.5)/ 4.1952 = 2.9796 > ________________________ F(Z) = 0.00144
Do we agree that 1022+0.5 = 11.5? Do we agree that 11.5/4.1952 = 2.7412? Do we agree that F(2.7412) = 0.003061?
I thought that you would appreciate that I was able to check out your calculations and correct the arithmetic. Or was it your BASIC program which did the miscalculation?
If the normal distribution used for the approximation has a smaller mean of 21.5 instead of 22, then the cdf must be larger for all x. So it should have been a red flag that you would get a smaller estimate with the CC than without the CC.
Jack
> The differences approxEXACT are respectively > > _______Without = +0.00056 > _______With C.C. = 0.00012. > ******** > > Jack´s response: > > The exact probablity calculated from the binomial > distribution is 0.0015595. The Afonso normal > approximation is 0.002115. The "improved" Afonso > normal approximation with a correction factor is > 0.003061, which is worse. Jack > > ******************************* > Licas

