Subject: Re: [office-comment] ODFF: CRITBINOM constraints on Alpha
Hi Eike, Eike Rathke schrieb:
Hi, On Wednesday, 2016-08-31 14:02:29 +0200, Eike Rathke wrote:6.18.19 CRITBINOM in Constraints says "Alpha >= 1", that makes no sense and instead should be "0 <= Alpha <= 1"Or better "0 < Alpha < 1" instead? Excel and Calc do not allow values 0.0 and 1.0, but Gnumeric does and returns 0 for Alpha=0 and number of trials for Alpha=1. Opinions?
I think Gnumeric calculates it correctly. CRITBINOM returns the smallest value k with P(X<=k) >= Alpha.For Alpha=0 the return value is always 0, because a probability is always >= 0 and therefore already P(X=0) fulfills >= Alpha=0.
For Alpha=1 it returns n besides in case p=0. For p<>0 you need to sum up all P(X=k) from k=0 to k=n to reach 1. Only in case p=0, already P(X=0)=1 >=Alpha=1 and therefore the return value is 0. [If an outcome is impossible, then the event X=0 is always true.]
The results for the cases Alpha=0 and Alpha=1 are mathematically well defined. So there is no need to exclude them.
That is my personal opinion. Kind regards Regina