# NEGBINOM.DIST

The `NEGBINOM.DIST` function returns the cumulative distribution probability of obtaining a certain number of failures before reaching a set number of successes in a negative binomial distribution. This function is commonly used in statistical analysis to model discrete random variables. The negative binomial distribution is often used to model the number of failures before a specified number of successes occur in a sequence of independent and identically distributed Bernoulli trials.

## Usage

Use the `NEGBINOM.DIST` formula with the syntax shown below, it has 3 required parameters:

Parameters:
1. num_failures (required):
The number of failures to occur.
2. num_successes (required):
The number of successes to stop at.
3. prob_success (required):
The probability of a success on each trial.

## Examples

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

### Probability of getting a certain number of failures before a set number of successes

You can use `NEGBINOM.DIST` to find the probability of obtaining a certain number of failures before reaching a set number of successes in a negative binomial distribution.

### Modeling discrete random variables

The negative binomial distribution is often used to model discrete random variables. You can use `NEGBINOM.DIST` to calculate probabilities for these types of models.

### Estimating probabilities of winning and losing in games

You can use `NEGBINOM.DIST` to estimate the probability of winning or losing a game based on the number of failures and successes needed to win the game.

## Common Mistakes

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

### Using the wrong order of arguments

One common mistake is to input the arguments in the wrong order. For NEGBINOM.DIST, the correct order is num_failures, num_successes, prob_success.

### Using a probability value outside of the range [0,1]

The prob_success argument should be a probability value between 0 and 1, inclusive. Using a value outside of this range will result in an error.

### Using non-numeric arguments

All arguments for NEGBINOM.DIST should be numeric values. Using non-numeric values will result in an error.

### Using inconsistent units for num_failures and num_successes

num_failures and num_successes should have consistent units. For example, if num_failures represents the number of failures before a specified number of successes, then num_successes should represent that specified number of successes.

### Misunderstanding what the output represents

NEGBINOM.DIST calculates the probability of getting a certain number of failures before a specified number of successes. It does not calculate the probability of getting a certain number of successes after a certain number of failures.

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

• `BINOM.DIST`

The `BINOM.DIST` function returns the probability of a certain number of successes in a fixed number of trials given a probability of success in each trial. It is most commonly used in statistical analysis and hypothesis testing. The function can calculate either the probability mass function (PMF) or the cumulative distribution function (CDF) depending on the value of the `cumulative` parameter.

• `POISSON.DIST`

The `POISSON.DIST` function calculates the Poisson distribution, which is a statistical distribution that shows how many times an event is likely to occur within a specified period of time, given the average rate of occurrence. This function is commonly used in probability theory to model the number of times an event occurs in a fixed interval of time or space. The resulting value represents the probability of the event occurring a certain number of times. If the cumulative argument is set to TRUE (or omitted), the function returns the cumulative distribution function; if set to FALSE, it returns the probability density function.

• `NORM.DIST`

The `NORM.DIST` formula is a statistical function that returns the normal distribution of a specified variable. It is used to determine the probability of a random variable falling within a specified range of values. This function is commonly used in finance and scientific research.

• `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.

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