BINOMDIST function

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Returns the individual term binomial distribution probability. Use BINOMDIST in problems with a fixed number of tests or trials, when the outcomes of any trial are only success or failure, when trials are independent, and when the probability of success is constant throughout the experiment. For example, BINOMDIST can calculate the probability that two of the next three babies born are male.

Syntax

BINOMDIST(number_s,trials,probability_s,cumulative)

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.

Remarks

  • Number_s and trials are truncated to integers.
  • If number_s, trials, or probability_s is nonnumeric, BINOMDIST returns the #VALUE! error value.
  • If number_s < 0 or number_s > trials, BINOMDIST returns the #NUM! error value.
  • If probability_s < 0 or probability_s > 1, BINOMDIST returns the #NUM! error value.
  • The binomial probability mass function is:

Equation

where:

Equation

is COMBIN(n,x).

The cumulative binomial distribution is:

Equation

Example

The example may be easier to understand if you copy it to a blank worksheet.

How to copy an example

  1. Create a blank workbook or worksheet.
  2. Select the example in the Help topic.

 Note    Do not select the row or column headers.

Selecting an example from Help

Fig. 1  Selecting an example from Help
  1. Press CTRL+C.
  2. In the worksheet, select cell A1, and press CTRL+V.
  3. To switch between viewing the results and viewing the formulas that return the results, press CTRL+` (grave accent), or on the Formulas tab, in the Formula Auditing group, click the Show Formulas button.
 
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A B
Data Description
6 Number of successes in trials
10 Number of independent trials
0.5 Probability of success on each trial
Formula Description (Result)
=BINOMDIST(A2,A3,A4,FALSE) Probability of exactly 6 of 10 trials being successful (0.205078)

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Applies to:
Excel 2007