Question using CRITBINOM

[lashio]

I have a Quality Control question using CRITBINOM().
My understanding is shown in cell(A7), but it does not seem right.
Will someone help me, please?

Sub Question_on_CRITBINOM()
Range("A1") = "Data"
Range("B1") = "Description"
Range("A2") = 25
Range("A3") = 0.5
Range("A4") = 0.01
Range("B2") = "Number of Bernoulli trials"
Range("B3") = "Probability of a success on each trial"
Range("B4") = "Criterion value"
Range("A6") = "=CRITBINOM(A2,A3,A4)"
Range("A7") = "=""For a "" & (1-A4)*100 & ""% success rate, a maximum of
rejects allowed is "" &A6 & "" out of "" & A2 & "" trials. If it is over
that, reject the whole lot."""
End Sub

[Conrad Carlberg]

You're getting the correct answer from CRITBINOM. Of course, your criterion
of 1% is very stringent. In effect, to use these arguments to CRITBINOM is
to ask:

Of 1000 lots, 10 of them (1%) have the 10 smallest number of defectives. I'm
testing 25 units in each of my 1000 lots, and 50% of the units are defective
in each lot. What is the largest number of defective units in the 10 lots
that have the smallest number of defective units?

With a 50% probability of a hit for each unit, it's very unusual (*** 1%) to
get only 1, 2, 3, 4, 5, 6 or 7 hits out of 25 trials.

To convince yourself that CRITBINOM returned the proper number, enter the
numbers 1 through 25 in A1:A25. In B1, enter this formula:

=BINOMDIST(A1,25,0.5,TRUE)

and copy-and paste that down into B2:B25. You'll note that for 6 successes,
BINOMDIST returns .007, and for 7 successes, BINOMDIST returns .02. This
conforms to the CRITBINOM definition, "Returns the smallest value for which
the cumulative binomial distribution is greater than or equal to a criterion
value." 7 is the number of successes associated with your criterion value,
..01, which is the smallest number greater than .007 in the binomial
distribution as you've defined it with your arguments.

C^2
Conrad Carlberg

"lashio" <lashio@worldnet.att.net> wrote in message
news:KZgAe.1117250$w62.972177@bgtnsc05-news.ops.worldnet.att.net...
> I have a Quality Control question using CRITBINOM().
> My understanding is shown in cell(A7), but it does not seem right.
> Will someone help me, please?
>
> Sub Question_on_CRITBINOM()
> Range("A1") = "Data"
> Range("B1") = "Description"
> Range("A2") = 25
> Range("A3") = 0.5
> Range("A4") = 0.01
> Range("B2") = "Number of Bernoulli trials"
> Range("B3") = "Probability of a success on each trial"
> Range("B4") = "Criterion value"
> Range("A6") = "=CRITBINOM(A2,A3,A4)"
> Range("A7") = "=""For a "" & (1-A4)*100 & ""% success rate, a maximum
of
> rejects allowed is "" &A6 & "" out of "" & A2 & "" trials. If it is over
> that, reject the whole lot."""
> End Sub
>
>

[lashio]

Hi, Conrad
Thank you very much for your detail explanation. I understand it better now.

"Conrad Carlberg" <carlbergc@earthlink.net> wrote in message
news:hfyAe.2117$dU3.950@newsread2.news.pas.earthlink.net...
> You're getting the correct answer from CRITBINOM. Of course, your
> criterion
> of 1% is very stringent. In effect, to use these arguments to CRITBINOM is
> to ask:
>
> Of 1000 lots, 10 of them (1%) have the 10 smallest number of defectives.
> I'm
> testing 25 units in each of my 1000 lots, and 50% of the units are
> defective
> in each lot. What is the largest number of defective units in the 10 lots
> that have the smallest number of defective units?
>
> With a 50% probability of a hit for each unit, it's very unusual (*** 1%)
> to
> get only 1, 2, 3, 4, 5, 6 or 7 hits out of 25 trials.
>
> To convince yourself that CRITBINOM returned the proper number, enter the
> numbers 1 through 25 in A1:A25. In B1, enter this formula:
>
> =BINOMDIST(A1,25,0.5,TRUE)
>
> and copy-and paste that down into B2:B25. You'll note that for 6
> successes,
> BINOMDIST returns .007, and for 7 successes, BINOMDIST returns .02. This
> conforms to the CRITBINOM definition, "Returns the smallest value for
> which
> the cumulative binomial distribution is greater than or equal to a
> criterion
> value." 7 is the number of successes associated with your criterion value,
> .01, which is the smallest number greater than .007 in the binomial
> distribution as you've defined it with your arguments.
>
> C^2
> Conrad Carlberg
>
> "lashio" <lashio@worldnet.att.net> wrote in message
> news:KZgAe.1117250$w62.972177@bgtnsc05-news.ops.worldnet.att.net...
>> I have a Quality Control question using CRITBINOM().
>> My understanding is shown in cell(A7), but it does not seem right.
>> Will someone help me, please?
>>
>> Sub Question_on_CRITBINOM()
>> Range("A1") = "Data"
>> Range("B1") = "Description"
>> Range("A2") = 25
>> Range("A3") = 0.5
>> Range("A4") = 0.01
>> Range("B2") = "Number of Bernoulli trials"
>> Range("B3") = "Probability of a success on each trial"
>> Range("B4") = "Criterion value"
>> Range("A6") = "=CRITBINOM(A2,A3,A4)"
>> Range("A7") = "=""For a "" & (1-A4)*100 & ""% success rate, a maximum
> of
>> rejects allowed is "" &A6 & "" out of "" & A2 & "" trials. If it is over
>> that, reject the whole lot."""
>> End Sub
>>
>>
>
>