In this tutorial, we will look at various ways for calculating the variance of lists in Python.

## Methods to Calculate Variance of Lists In Python

Before we dive into the methods to calculate the variance of lists, let’s understand what variance means.

**Variance **is a crucial mathematical tool in statistics. It’s used to deal with massive volumes of data. For a given data collection, it is the square of the standard deviation.

Variance is also known as a distribution’s second central moment. The mean of the square minus the square of the mean of a given data set is used to compute it.

*Variable (X) = E[(X- )2]*

## Method 1: Python variance function

Python includes a built-in function for computing the variance of lists. The syntax, as well as an explanation of its arguments, is provided below.

```
variance( [data], mean )
```

[data]: It provides a list of the data for which the variance is to be computed.

mean: It is a non-mandatory parameter. It uses the actual mean’s value.

## Method 2: The Rudimentary method

This is the most basic way of computing the variance of lists. In the following example, we compute the mean and subsequently the variance using the above-mentioned formula.

We are not using any of the built-in methods here and instead calculating the variance of lists manually by building out the formula.

```
l = [1, 2, 3, 4, 5, 6]
print("The original list is : " + str(l))
length= int(len(l))
mean = sum(l) / length
ans = sum((i - mean) ** 2 for i in l) / length
print("The variance of list is : " + str(ans))
```

The output of the code is as follows:

```
The original list is : [1, 2, 3, 4, 5, 6]
The variance of list is : 2.9166666666666665
```

## Method 3: Using statistics Module

In this example, we utilize the built-in function variance() which makes calculating the variance of lists very easy.

```
import statistics
list1 = [1, 2, 3, 4, 5, 6]
print("The original list is : " + str(list1))
ans = statistics.variance(list1)
print("The variance of list is : " + str(ans))
```

The output of the code is as follows:

```
The original list is : [1, 2, 3, 4, 5, 6]
The variance of list is : 3.5
```

## Conclusion

Congratulations! You just learned three different ways to compute the variance of a list using the Python programming language. Hope you enjoyed it! 😇

Liked the tutorial? I would recommend you to have a look at the tutorials mentioned below:

- Compute a^n in Python: Different Ways to Calculate Power in Python
- How to Compute Distance in Python? [ Easy Step-By-Step Guide ]

Thank you for taking your time out! Hope you learned something new!! 😄