Curriculum
Course: SCIPY
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Text lesson

KS-Test

The KS test is used to determine if given values follow a specific distribution.

The function takes the values to be tested and the cumulative distribution function (CDF) as two parameters.

A CDF can be either a string representing a predefined distribution or a callable function that returns the probability.

It can be used as either a one-tailed or two-tailed test.

By default, it is a two-tailed test. We can specify the alternative parameter as a string, with options “two-sided,” “less,” or “greater.”

Example

Determine if the given value follows a normal distribution.

import numpy as np
from scipy.stats import kstest

v = np.random.normal(size=100)

res = kstest(v, ‘norm’)

print(res)

Result:

KstestResult(statistic=0.047798701221956841, pvalue=0.97630967161777515)

Statistical Description of Data

To get a summary of values in an array, we can use the describe() function.

It returns the following statistics:

  • Number of observations (nobs)
  • Minimum and maximum values (minmax)
  • Mean
  • Variance
  • Skewness
  • Kurtosis

Example

Display the statistical summary of the values in an array.

import numpy as np
from scipy.stats import describe

v = np.random.normal(size=100)
res = describe(v)

print(res)

Result:

DescribeResult(

nobs=100,

minmax=(-2.0991855456740121, 2.1304142707414964),

mean=0.11503747689121079,

variance=0.99418092655064605,

skewness=0.013953400984243667,

kurtosis=-0.671060517912661

)