Measures of dispersion - range, quartile deviation, mean deviation, standard deviation, Coefficient of variation
MEASURES OF DISPERSION (CONCEPTUAL NOTES) 1. Introduction Measures of dispersion show how spread out or scattered the data are. While the mean, median, and mode tell us about the central value, dispersion tells us how far the data are from the center. Two datasets can have the same mean but different spreads, so dispersion helps us understand variability or consistency. Common measures: Range Quartile Deviation (Q.D.) Mean Deviation (M.D.) Standard Deviation (S.D.) Coefficient of Variation (C.V.) 2. Range Definition: The range is the difference between the largest and smallest values in the data. Purpose: Gives a quick idea of how spread out the data is. Advantages: Very simple and easy to calculate. Disadvantages: Uses only two values, ignoring the rest of the data. Very sensitive to extreme values or outliers. 3 . Quartile Deviation (Q.D.) Definition: Quartile deviation measures the spread of the middle 50% of the data. It focuses on the central part of the dataset, ignoring extreme ...