Machine Learning - Mean Median Mode

Mean, Median, and Mode What can we learn from looking at a group of numbers? In Machine Learning (and in mathematics) there are often three values that interests us:

• The average value

• The mid point value

• The most common value

Example: We have registered the speed of 13 cars: speed = [99,86,87,88,111,86,103,87,94,78,77,85,86] What is the average, the middle, or the most common speed value?

The mean value is the average value. To calculate the mean, find the sum of all values, and divide the sum by the number of values:

89.77 The NumPy module has a method for this. Learn about the NumPy module in our NumPy Tutorial.

method to find the average speed: import numpy speed = [99,86,87,88,111,86,103,87,94,78,77,85,86]

The median value is the value in the middle, after you have sorted all the values: 77, 78, 85, 86, 86, 86, 87, 87, 88, 94, 99, 103, 111 It is important that the numbers are sorted before you can find the median. The NumPy module has a method for this:

method to find the middle value: import numpy speed = [99,86,87,88,111,86,103,87,94,78,77,85,86]

If there are two numbers in the middle, divide the sum of those numbers by two. 77, 78, 85, 86, 86, 86, 87, 87, 94, 98, 99, 103

86.5

import numpy speed = [99,86,87,88,86,103,87,94,78,77,85,86]

The Mode value is the value that appears the most number of times: 99, 86, 87, 88, 111, 86, 103, 87, 94, 78, 77, 85, 86 = 86 The SciPy module has a method for this. Learn about the SciPy module in our SciPy Tutorial.

method to find the number that appears the most: from scipy import stats speed = [99,86,87,88,111,86,103,87,94,78,77,85,86]

The Mean, Median, and Mode are techniques that are often used in Machine Learning, so it is important to understand the concept behind them.