# Microsoft Knowledge Base

## Excel: Using the BINOMDIST() Function

Last reviewed: September 12, 1996

Article ID: Q100121

The information in this article applies to:

- Microsoft Excel for Windows, versions 4.0, 4.0a, 5.0
- Microsoft Excel for the Macintosh, version 4.0

## SUMMARY

The BINOMDIST() function returns the individual term binomial distribution probability.

When you use the BINOMDIST function, you make the following three assumptions:

- The outcome of each trial is only success or failure. -and-
- The trials are independent. -and-
- The probability of success is constant throughout the experiment.

## MORE INFORMATION

The following is the syntax for the BINOMDIST() function,

BINOMDIST(number_s,trials,probability_s,cumulative)

where:

NUMBER_S is the number of successes in trials TRIALS is the number of independent trials PROBABILITY_S is the probability of success on each trial CUMULATIVE is a logical value that determines the form of the function

If cumulative is TRUE, then BINOMDIST() returns the cumulative distribution function, which is the probability that there are at most number_s successes; if FALSE, it returns the probability mass function, which is the probability that there are number_s successes.

If number_s <0 or number_s> trials, BINOMDIST() returns #NUM.

If probability_s <0 or probability_s> 1, BINOMDIST() returns #NUM.

For example, in a population of software engineers, 9 out of 10 recommend 5.25-inch disks. What is the probability of choosing two engineers at random and finding that neither of them recommends 5.25-inch disks?

To calculate the following values in a BINOMDIST() function,

number_s = 0 trials = 2 probability_s = 0.9 cumulative = false

you would use the formula, BINOMDIST(0,2,0.9,false). This formula returns a result of 0.01 or 1%.

KBCategory: kbusage Last reviewed: September 12, 1996 |