# BINOMDIST

The `BINOMDIST` function calculates the probability of a certain number of successes in a fixed number of trials given a constant probability of success for each trial. This function is commonly used in statistical analysis and hypothesis testing.

## Usage

Use the `BINOMDIST` formula with the syntax shown below, it has 3 required parameters and 1 optional parameter:

Parameters:
1. num_successes (required):
The number of successes to calculate the probability for. Must be a non-negative integer.
2. num_trials (required):
The total number of trials. Must be a positive integer.
3. prob_success (required):
The probability of success for each trial. Must be a number between 0 and 1, inclusive.
4. cumulative (optional):
A boolean value indicating whether to calculate the cumulative probability up to and including the given number of successes. If omitted or false, only the probability of exactly the given number of successes is calculated.

## Examples

Here are a few example use cases that explain how to use the `BINOMDIST` formula in Google Sheets.

### Calculating the probability of a certain number of coin flips resulting in heads

Suppose you flip a fair coin 10 times. You want to know the probability of getting exactly 5 heads. You can use `BINOMDIST` to calculate this probability.

### Calculating the probability of a certain number of defective items in a sample

Suppose you have a sample of 100 items from a production line that has a known defect rate of 5%. You want to know the probability that exactly 3 of the items in the sample are defective. You can use `BINOMDIST` to calculate this probability.

### Calculating the cumulative probability of at most a certain number of successes

Suppose you flip a fair coin 10 times. You want to know the probability of getting at most 5 heads. You can use `BINOMDIST` with the cumulative parameter set to true to calculate this probability.

## Common Mistakes

`BINOMDIST` not working? Here are some common mistakes people make when using the `BINOMDIST` Google Sheets Formula:

### Incorrect number of arguments

One of the most common mistakes is providing an incorrect number of arguments to the BINOMDIST formula. Make sure you have provided the correct number of arguments and that they are in the correct order.

### Incorrect data types

Make sure that you are providing the correct data types for each argument. For example, num_successes and num_trials should be integers, and prob_success should be a decimal between 0 and 1.

### Incorrect probability

Another common mistake is providing an incorrect probability value for prob_success. Make sure you are using the correct probability value for your calculations.

### Incorrect cumulative value

If you set the cumulative argument to TRUE, the formula will return the cumulative distribution function. If you set the cumulative argument to FALSE or leave it blank, the formula will return the probability mass function. Make sure you are using the correct cumulative value for your calculations.

The following functions are similar to `BINOMDIST` or are often used with it in a formula:

• `BINOM.INV`

The `BINOM.INV` formula calculates the smallest value for which the cumulative binomial distribution is less than or equal to a specified criterion value. It is commonly used in statistics to find the exact number of successes in a fixed number of independent trials with a known probability of success.

• `POISSON`

The `POISSON` function returns the Poisson distribution probability density function, which is used to show the probability of a certain number of events occurring in a fixed interval of time or space. It takes in the values for the number of events (x), the mean (mean), and a boolean for whether or not to return the cumulative distribution (cumulative).

• `T.DIST`

The `T.DIST` function returns the probability of a Student's t-distribution with a specified degrees of freedom. This function is usually used in hypothesis testing to determine the probability that a sample mean is within a specified range of values.

• `Z.TEST`

The `Z.TEST` formula returns the probability of a certain value occurring in a normal distribution. This formula is commonly used to test whether two samples have the same mean by comparing their Z scores. The formula returns a value between 0 and 1, with a result closer to 1 indicating a higher likelihood that the value could occur by chance.

You can learn more about the `BINOMDIST` Google Sheets function on Google Support.