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# Probability Mass Function and Probability Density Function

## What are Probability Mass Function and Probability Density Function?

Probability Mass Function:

The first function is known as the probability mass function (PMF). This function returns the probability that a random variable takes a certain value. Because the PMF returns probabilities, any PMF must have two properties.

1. The value returned from a PMF must be non-negative.
2. The sum across all values supporting a random variable must be one.

Probability Density Function:

PDF is a probability that a random variable, say X, will take a value equal to x. The probability density function (PDF) for any values of y and n can be computed using basic probability.

The pdf f(x) has two important properties:

1. f(x)≥ 0f (x)≥0, for all x
2. $\int_{\infty }^{\infty}$ f(x)dx = 1

## Example of Probability Mass Function and Probability Density Function:

The formula of pdf is:
$f\left ( x \right )= \frac{d}{dx}F\left (x \right )$

The formula pmf is:

A PMF equation looks like this: P(X = x).
That means “the probability that X takes on some value x”.

Owais Siddiqui
1 min read

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