Skewness: If a histogram/frequency polygon of a distribution is asymmetric, the distribution is said to be skewed.
If the distribution is not symmetric because its graph extends further to the right than to the left, that is, if it has a long tail to the right, we say that the distribution is skewed to the right or it is positively skewed.
A distribution will be skewed to the right, or positively skewed, if its mean is greater than its mode.
If the distribution is not symmetric because its graph extends further to the left than to the right, that is, if it has a long tail to the left, we say that the distribution is skewed to the left or it is negatively skewed.
A distribution will be skewed to the left, or negatively skewed, if its mean is less than its mode.
Skewness >0 indicates positive skewness
<0 indicates negative skewness
Kurtosis: it is a measure of the degree to which the distribution is peaked or flat in comparison to a normal distribution whose graph is characterized by a bell shaped appearance.
Platykurtic: the graph exhibits a flattened appearance
Mesokurtic: normal, bell shaped graph
Leptokurtic: the graph exhibits a more peaked appearance
Platykurtic kurtosis <0
Mesokurtic kurtosis =0
Leptokurtic kurtosis >0
Kurtosis: it is a measure of the degree to which the distribution is peaked or flat in comparison to a normal distribution whose graph is characterized by a bell shaped appearance.
Platykurtic: the graph exhibits a flattened appearance
Mesokurtic: normal, bell shaped graph
Leptokurtic: the graph exhibits a more peaked appearance
PSM / COMMUNITY MEDICINE by Dr Abhishek Jaiswal is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.
Based on a work at learnpsm@blogspot.com.
Permissions beyond the scope of this license may be available at jaiswal.fph@gmail.com.
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