Statistics
Two classes can share the same average yet differ widely in spread, so averages alone mislead. Chapter 13, Statistics, of the NCERT Mathematics textbook for Class 11 measures dispersion around the centre. You will compute range and quartile deviation, find mean deviation about mean and median for grouped and ungrouped data, and calculate variance and standard deviation with shortcut methods. Comparisons of batsmen, machines and markets show why spread matters as much as centre.
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