Skewness and Kurtosis

Skewness

The coefficient of Skewness is a measure for the degree of symmetry in the variable distribution (Sheskin, 2011).

Skewness: negatively skewed distribution Skewness: normal distribution Skewness: positively skewed distribution
Negatively skewed distribution
or Skewed to the left
Skewness <0
Normal distribution
Symmetrical
Skewness = 0
Positively skewed distribution
or Skewed to the right
Skewness > 0

 

Kurtosis

The coefficient of Kurtosis is a measure for the degree of tailedness in the variable distribution (Westfall, 2014).

Kurtosis: platykurtic distribution Kurtosis: normal distribution Kurtosis: leptokurtic distribution
Platykurtic distribution
Thinner tails
Kurtosis <0
Normal distribution
Mesokurtic distribution
Kurtosis = 0
Leptokurtic distribution
Fatter tails
Kurtosis > 0

Literature

  • Sheskin DJ (2011) Handbook of parametric and nonparametric statistical procedures. 5th ed. Boca Raton: Chapman & Hall /CRC. Book info
  • Westfall PH (2014) Kurtosis as Peakedness, 1905 - 2014. R.I.P. The American Statistician 68:191-195. PubMed

See also

External links