Statistical Functions in Python | Set 2 (measure of distribution)

A measure of the spread of statistics functions is discussed in this article.

1. variance () : — this function calculates variance, i.e.  a measure of data bias, the larger the variance value, the more scattered the data values ​​. The sample variance is calculated in this function, assuming the data are for the population. If the passed argument is empty, StatisticsError is thrown.

2. pvariance () : — this function calculates the variance of the entire population . The data is interpreted as the entire population. If the passed argument is empty, StatisticsError is raised.

# Python code to demonstrate how it works
# variance () and pvariance ()

 
# import statistics for processing statistical operations

import statistics

 
# initializing list

li = [ 1.5 , 2.5 , 2.5 , 3.5 , 3 .5 , 3.5 ]

 
# using variance to calculate data variance

print ( " The variance of data is: " , end = "")

print (statistics.variance (li))

 
# using pvariance to calculate variance of population data

print ( "The population variance of data is:" , end = "")

print (statisti cs.pvariance (li))

Output:

 The variance of data is: 0.6666666666666667 The population variance of data is: 0.5555555555555556 

3. stdev () : — This function returns the standard deviation (square root of sample variance) of the data. If the passed argument is empty, StatisticsError is thrown.

4. pstdev () : — This function returns the standard deviation of a population of (square root of the population variance) of the data. If the passed argument is empty, StatisticsError is raised.

# Python code to demonstrate how it works
# stdev () and pstdev ()

 
# import statistics for processing statistical operations

import statistics

 
# initializing list

li = [ 1.5 , 2.5 , 2.5 , 3.5 , 3.5 , 3.5 ]

 
# using stdev to calculate the standard deviation of the data

print ( "The standard deviation of data is:" , end = "")

print (statistics.stdev (li))

 
# using pstdev to calculate the standard deviation of population data

print ( "The population standard deviation of data is:" , end = "")

print (statistics.pstdev (li))

Output:

 The standard deviation of data is: 0.816496580927726 The population standard deviation of data is: 0.7453559924999299 

This article is courtesy of Manjeet Singh . If you are as Python.Engineering and would like to contribute, you can also write an article using contribute.python.engineering or by posting an article contribute @ python.engineering. See my article appearing on the Python.Engineering homepage and help other geeks.

Please post comments if you find anything wrong or if you would like to share more information on the topic discussed above.