Explain the various methods of measuring Skewness.
3 years ago
Business Statistics
Measures of skewness are meant to give an idea about the direction and degree of asymmetry in a variable. These measures can be absolute or relative.
Methods of Measuring Skewness :
- Karl Pearson’s Measure : This measure is based on statistical
(a) Absolute Measure (Skewness) (Sk) :
Sk = X - Z or Sk = 3(X - M)
(b) Relative Measure or Coefficient of Skewness (J) :
J = X - Z or J = 3(X - M)
σ σ
The direction of skewness is represented by algebraic sign, if it is plus, skewness is positive. If it is minus, skewness is negative.
- Bowley’s Measure or Quartiles Measure : Bowley‘s measure of skewness is called second measure of skewness. This measure is useful in distributions where mode is ill-defined and can also be used in open end
SkQ = Q3 = Q1—2M
and Coefficient of skewness (JQ) = Q3 + Q1 - 2M
Q3 - Q1
- Kelly’s Measure : It is based on 90% observations and calculated from percentiles and
|
and |
Skewness = P90 + P10 – P50 Coefficient of Skewness (Jp) = P90 + P10 – P50 |
or or |
D9 + D1 – D5 D9 + D1 – D5 |
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P90 - P10 |
|
D9 - D1 |
Surya Bikram Bhandari
Nov 14, 2021