NEGBINOMDIST

The NEGBINOMDIST function calculates the probability of a specified number of failures before achieving a target number of successes, based on a negative binomial distribution. This function is commonly used in statistical analysis to model scenarios where success and failure outcomes occur repeatedly until a certain number of successes is reached.

Syntax

=NEGBINOMDIST(`Number_f`, `Number_s`, `Probability_s`)

When analyzing scenarios involving repeated trials with success and failure outcomes, the NEGBINOMDIST function in Excel proves to be a valuable tool. This function is particularly useful for situations where the goal is to determine the likelihood of encountering a specified number of failures before achieving a desired number of successes, following a negative binomial distribution pattern. It aids in understanding the probability associated with the number of attempts required to reach the designated success milestone in a series of trials.

Examples

Suppose you are conducting a series of experiments with a success probability of 0.3 per trial. You want to calculate the probability of encountering 5 failures before achieving 3 successes. The NEGBINOMDIST formula would be:
=NEGBINOMDIST(5, 3, 0.3)
This will return the probability of experiencing 5 failures before obtaining 3 successes in the given trials.

In another scenario with a success probability of 0.6 per trial, you wish to determine the likelihood of having 2 failures before reaching 4 successes. The NEGBINOMDIST formula would be:
=NEGBINOMDIST(2, 4, 0.6)
This calculation provides the probability of encountering 2 failures before attaining 4 successes in the experiment.

Notes

Ensure the input values for Number_f, Number_s, and Probability_s are accurate representations of the scenario under analysis. The NEGBINOMDIST function assumes a negative binomial distribution, where the probability of success remains constant across all trials. It is essential to interpret the results in the context of the specific experiment being modeled.

Questions

What does the NEGBINOMDIST function calculate?

The NEGBINOMDIST function calculates the probability of encountering a specified number of failures before achieving a target number of successes in a series of repeated trials following a negative binomial distribution pattern.

In what scenarios is the NEGBINOMDIST function commonly used?

The NEGBINOMDIST function is commonly used in statistical analysis to model situations where success and failure outcomes occur repeatedly until a specific number of successes is reached. It helps in understanding the likelihood of achieving a set number of successes after a certain number of failures.

Can the NEGBINOMDIST function handle varying probabilities of success across trials?

No, the NEGBINOMDIST function assumes a constant probability of success across all trials in its calculations. It operates based on this assumption to determine the probability of reaching the target number of successes after a specified number of failures.

How can the results from the NEGBINOMDIST function be interpreted?

The results obtained from the NEGBINOMDIST function represent the probability associated with encountering a specific number of failures before achieving the desired number of successes in a series of repeated trials. This information aids in assessing the likelihood of reaching the success milestone under consideration.