R help - Apr 2023 - simultaneous confidence intervals for multinomial proportions: sample size

Hello!
I want to calculate simultaneous confidence intervals for a nominal variable
with three categories: "yes", "no", "partially"
and I expect that far more than 5 samples fall into each category.
I have read that Glaz & Sison's method is only appropriate for variables
with 7 or more categories. Therefore, the Goodman method seems like a good idea.
I have found the R function "MultinomCI" {DescTools} to calculate
these CIs.
However, I have not found a way to calculate in advance the required sample size
for the Goodman method at a fixed confidence level and length of the intervall.
I would be very grateful for any suggestion.


Many thanks in advance!

Claudia


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> On Apr 9, 2023, at 5:46 AM, paladini at trustindata.de wrote:
> 
> Hello!
> I want to calculate simultaneous confidence intervals for a nominal
variable with three categories: "yes", "no",
"partially" and I expect that far more than 5 samples fall into each
category.
> I have read that Glaz & Sison's method is only appropriate for
variables with 7 or more categories. Therefore, the Goodman method seems like a
good idea.
> I have found the R function "MultinomCI" {DescTools} to calculate
these CIs.
> However, I have not found a way to calculate in advance the required sample
size for the Goodman method at a fixed confidence level and length of the
intervall.


Seems very unlikely that you can achieve both of those goals simultaneously. I
would expect the CI width t vary with the size of the sample in each category in
any case. So I'm wondering if your failure at searching derives from the
impossibility of your goal. Why would you desire such a result?


-- 
David.
> I would be very grateful for any suggestion.
> 
> 
> Many thanks in advance!
> 
> Claudia
> 
> 
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> 
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