How to Calculate Standard Deviation ?

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HOW TO CALCULATE STANDARD DEVIATION ?
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Standard Deviation

• The measure of how much the data is spread out
  form the mean is called as standard deviation.
• It is expresses in sigma.
• The higher the dispersion, the higher standard
  deviation.

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Standard Deviation
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Standard Deviation Calculation

• To calculate standard deviation, mean and
  varaiance shoul be known.
• Lets consider an example for simple understanding.

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Standard Deviation Example

• Measure the height of all the person's in your
  home.
• If your home contains four members and their
  height's are
• A 165
• B 145
• C 153
• D 150

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Standard Deviation - Mean

• Now you have to find the mean of the heights
  measured.
• Mean is nothing but average.
• Mean 165 145 153 150
• 4
• 500.5

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Standard Deviation - Variance

• Next step is to find the variance.
• It is the average of the squares of the
  differences from mean.
• Subtract individual heights from the mean and
  square each value.

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Standard Deviation - Variance

• A (165 - 153.25) (11.75)2 138.0625
• B (145 - 153.25) (-8.25)2 68.0625
• C (153 - 153.25) (-0.25)2 0.0625
• D (150 - 153.25) (-3.25)2 10.5625
• Variance 138.0625 68.06250.062510.5625
• 4 -
  1
• 72.25

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Standard Deviation

• Now Standard Deviation Square root (Variance)
• Square root
  ( 72.25)
• 8.5
• For population standard deviation, we would
  calculate variance without subtracting 1 from the
  denominator.

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Thank You!

• Calculate standard deviation online with Standard
  Deviaton Calculator
• https//www.easycalculation.com/statistics/standar
  d-deviation.php