What is Skewness?
Skewness is a statistical measure that describes the asymmetry of a data distribution. It indicates whether the data points are more spread out on one side of the distribution’s mean than the other. Skewness can be positive, negative, or zero, each providing insights into the shape of the distribution.
Types of Skewness
Skewness can be classified into two main types:
- Positive Skewness
- Negative Skewness
Positive Skewness (Right Skew)
A distribution is said to be positively skewed when the tail on the right side of the distribution is longer or fatter than the tail on the left side.
In a positively skewed distribution, the mean is greater than the median, which is greater than the mode. This means that the distribution has a longer tail towards the right side, with a few extreme values pulling the mean towards the right.
Example: Income distribution in many countries is often positively skewed, with a small number of individuals having very high incomes, while the majority have lower to moderate incomes.
Negative Skewness (Left Skew)
A distribution is said to be negatively skewed when the tail on the left side of the distribution is longer or fatter than the tail on the right side.
In a negatively skewed distribution, the mean is less than the median, which is less than the mode. This means that the distribution has a longer tail towards the left side, with a few extreme values pulling the mean towards the left.
Example: The distribution of test scores in a class where most students perform well but a few students perform poorly can result in a negatively skewed distribution.
Coefficient of Skewness
Coefficient of Skewness is a statistical measure that indicates the asymmetry of data around its mean, revealing whether the data is skewed to the left, right, or is symmetrical.
By identifying the direction and degree of skewness, researchers can gain insights into the underlying patterns and characteristics of the data. In this article, we will discuss all the Coefficient of Skewness i.e., Pearson’s Coefficient, Bowley’s Coefficient, and Kelly’s Coefficient.
Table of Content
- What is Skewness?
- Types of Skewness
- What is Coefficient of Skewness?
- Pearson’s First Coefficient of Skewness
- Pearson’s Second Coefficient of Skewness
- Bowley’s Coefficient of Skewness
- Kelly’s Coefficient of Skewness
- Interpreatation of Coefficient of Skewness
- FAQs
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