Checking the variance of a dataset

Just like we may want to know where the center of a dataset lies, we may also want to know how widely spread the dataset is, for example, how far apart the numbers in the dataset are from each other. The variance helps us achieve this. Unlike the mean, median, and mode, which give us a sense of where the center of the dataset lies, the variance gives us a sense of the spread of a dataset or the variability.

It is a very useful statistic, especially when used alongside a dataset’s mean, median, and mode.

To analyze the variance of a dataset, we will use the var method from the numpy library in Python.

Getting ready

We will work with the COVID-19 cases again for this recipe.

How to do it…

We will compute the variance using the numpy library:

1. Import the numpy and pandas libraries:

   import numpy as np
   import pandas as pd

2. Load the .csv into a dataframe using read_csv. Then subset the dataframe to include only...