# EXPONDIST

The `EXPONDIST` function calculates the probability of an event occurring at a specific time, assuming that the events follow an exponential distribution. It is commonly used in reliability analysis to model the time between failures of a system.

## Usage

Use the `EXPONDIST` formula with the syntax shown below, it has 3 required parameters:

Parameters:
1. x (required):
The value at which to evaluate the function.
2. LAMBDA (required):
The rate parameter of the distribution.
3. cumulative (required):
A boolean indicating whether to return the cumulative distribution function (true) or the probability density function (false).

## Examples

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

### Calculate the probability of an event occurring within a specific time frame

By using `EXPONDIST` with cumulative set to true, you can determine the probability that an event will occur within a given time frame, given a known rate of occurrence.

### Model time between failures

Using `EXPONDIST`, you can model the time between failures of a system and estimate the probability of failure within a given time frame.

## Common Mistakes

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

### Missing arguments

The EXPONDIST formula requires three arguments: x, LAMBDA, and cumulative. Make sure all three arguments are included in the formula.

### Incorrect argument order

Make sure you are entering the arguments for the EXPONDIST formula in the correct order: x, LAMBDA, and cumulative.

### Invalid input type

The x and LAMBDA arguments must be numeric values. Make sure you are not entering any non-numeric characters or text strings.

### Incorrect cumulative value

The cumulative argument should be either TRUE or FALSE, depending on whether you want to calculate the cumulative or probability density function, respectively.

### Incorrect lambda value

The lambda value should be a positive number. Make sure you are entering a valid value for lambda.

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

• `NORMDIST`

The `NORMDIST` function in Google Sheets calculates the normal distribution for a specified value, mean, and standard deviation. It returns the probability of a value occurring within a specified range of a normal distribution. It is commonly used in statistics, finance, and science to analyze data and make predictions.

• `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.

• `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).

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