ML – Standard deviation and Variance

Standard deviation is a number that describes how spread out the values are.A low standard deviation means that most of the numbers are close to the mean (average) value.A high standard deviation means that the values are spread out over a wider range.

Example: This time we have registered the speed of 7 cars:

import numpy

speed = [86,87,88,86,87,85,86]

x = numpy.std(speed)

print(x)

```0.9035079029052513

import numpy

speed = [32,111,138,28,59,77,97]

x = numpy.std(speed)

print(x)

37.84501153334721

# Find the Variance
import numpy

speed = [32,111,138,28,59,77,97]

x = numpy.var(speed)

print(x)

1432.2448979591834

import numpy

speed = [86,87,88,86,87,85,86]

x = numpy.var(speed)

print(x)

0.8163265306122449

Symbols
Standard Deviation is often represented by the symbol Sigma: σ
Variance is often represented by the symbol Sigma Square: σ2```