The CRITBINOM function in Excel calculates the inverse of the Cumulative Binomial Distribution. In other words, for a given number of independent trials, the function returns the least value (number of successes) whose cumulative binomial distribution is higher than or equal to a given value. For example, the Critbinom method will be used to calculate the fewest number of permutations with a 50% likelihood with at least 20 heads.
Syntax:
=CRITBINOM( trials, probability_s, alpha )
Parameter:
trials:
(If this number is a decimal, Excel truncates it to an integer.)
probability_s:
alpha :
Example :
The graph on the right depicts the Cumulative Binomial Distribution Function for 100 coin tosses. This curve depicts the likelihood that x heads will be tossed out of a total of 100 tosses.
The inverse of the curve on the right is calculated using the Excel Critbinom function. In other words, the Critbinom function computes the smallest value of x for which the Cumulative Binomial Distribution function returns a given value. The spreadsheets below demonstrate this for three distinct criteria values.
Ask Your Query