Learn to calculate the measures of variability (variance and standard deviation) of a data set usign the statistics module provided by the Python standard library in my blog post here.

Mean, median and mode are measures of central tendency. In other words, they are used to represent the a central value in a set of values.

Mean

Mean is the average value in a set of values.

We can calculate the mean of a data set by dividing the sum of values by the count of values.

Median

Median is the middle value in an ordered list of values.

When there are odd numbers of data points, the median is always the middle number. In case there are even numbers of data points, the median is the average of the two middle numbers.

The median represents the 50th percentile of our data. This means that 50% of the values are greater than the median and 50% of the data are less than the median.

Mode

The mode of a data set is the most frequently occurring value.

The Python standard library’s statistics module provides functions for calculating mean, median and mode.

First, we import the statistics module. Then we can access the module’s functions using the name of the module followed by a dot followed by the name of the function to call.

Example:

import statistics

scores = [34, 45, 67, 38, 89, 45, 98, 12, 24]

mean = statistics.mean(scores)
print(mean)
# 50.22

median = statistics.median(scores)
print(median)
# 45

mode = statistics.mode(scores)
print(mode)
# 45