Site pages

Current course

Participants

General

Topic 1

Topic 2

Topic 3

Topic 4

Topic 5

Topic 6

Topic 7

Topic 8

Topic 9

Topic 10

Topic 11

Topic 12

Topic 13

Topic 14

Topic 15

Topic 16

Topic 17

Topic 18

Topic 19

## 8.1.2 Measures of skewness

Various measures of skewness are 1) S Where M is the mean, M 3) S These are the absolute measures of skewness. As in dispersion, for comparing two series we do not calculate these absolute measures but we calculate the relative measures called the co-efficients of skewness which are pure numbers independent of units of measurement. The following are the co-efficients of skewness: 1) Prof. Karl Pearson’s Co-efficient of Skewness where s is the standard deviation of the distribution It has been shown that for any distribution, (M-M Skewness is positive if M> M 2. Prof. Bowley’s Co-efficient of Skewness Based on quartiles, Thus Sk = + 1 if Md = Q1 and Sk = -1 if Q3 = Md. Bowley’s co-efficient of skewness lies between 3. Based upon moments, co-efficient of skewness is Where symbols have their usual meanings. Thus Sk = 0 if either b We observe in (1) and (2) that skewness can be positive as well as negative. The skewness is positive if the larger tail of the distribution lies towards the higher values of the variate (the right), i.e. if the curve drawn with the help of the given data is stretched more to the right than to the left and is negative in the contrary case. |