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

File handling | Python Methods and Functions

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

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