CRITBINOM function
Returns the smallest value for which the cumulative binomial distribution is greater than or equal to a criterion value. Use this function for quality assurance applications. For example, use CRITBINOM to determine the greatest number of defective parts that are allowed to come off an assembly line run without rejecting the entire lot.
Important This function has been replaced with one or more new functions that may provide improved accuracy and whose names better reflect their usage. Although this function is still available for backward compatibility, you should consider using the new functions from now on, because this function may not be available in future versions of Excel.
For more information about the new function, see BINOM.INV function.
Syntax
CRITBINOM(trials,probability_s,alpha)
The CRITBINOM function syntax has the following arguments:

Trials Required. The number of Bernoulli trials.

Probability_s Required. The probability of a success on each trial.

Alpha Required. The criterion value.
Remarks

If any argument is nonnumeric, CRITBINOM returns the #VALUE! error value.

If trials is not an integer, it is truncated.

If trials < 0, CRITBINOM returns the #NUM! error value.

If probability_s is < 0 or probability_s > 1, CRITBINOM returns the #NUM! error value.

If alpha < 0 or alpha > 1, CRITBINOM returns the #NUM! error value.
Example
Copy the example data in the following table, and paste it in cell A1 of a new Excel worksheet. For formulas to show results, select them, press F2, and then press Enter. If you need to, you can adjust the column widths to see all the data.
Data 
Description 

6 
Number of Bernoulli trials 

0.5 
Probability of a success on each trial 

0.75 
Criterion value 

Formula 
Description 
Result 
=CRITBINOM(A2,A3,A4) 
Smallest value for which the cumulative binomial distribution is greater than or equal to a criterion value 
4 