Coefficient of Skewness and Skewness

Before study coefficient  of skewness firstly we will understand the meaning of skewness

Skewness:

It is degree of distortion from symmetric normal or bell curve 

Skewness may be positive, negative, zero or undefined

Majorly there are two type of skewness

Positively skewed:

if the tail on the right side of the distribution is longer 

Mean  and median  of positively skewed data will be greater than the mode

mean > mode and median > mode 

Negatively skewed:

if the tail on the left  side of the distribution is longer 

mean

There are several ways to measure skewness.

Pearson’s first and second coefficients of skewness are two common ones.

Person first coefficient if skewness  or Pearson mode skewness,

It subtracts the mode from the mean and divides the difference by the standard deviation.

Pearson’s second coefficient of skewness

Pearson median skewness

It subtracts the median from the mean, multiplies the difference by three and divides the product by the standard deviation.