Maths · Class 11 · Chapter 13

Statistics

11 lessons96 min4 simulations

Averages locate the centre of data; this chapter measures how the data spread around it. It starts from range, builds mean deviation about the mean and about the median for raw data, discrete frequency tables and class intervals, and explains why mean deviation is not enough. It then defines variance and standard deviation, computes them for raw and grouped data by the direct, alternative and step-deviation methods, and shows how shifting, scaling or correcting data changes them.

Also called: mean deviation · variance and standard deviation

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Lessons

11 lessons · 96 min

01Why spread mattersNCERT §13.17 min 02RangeNCERT §13.2, §13.37 min 03Mean deviation for ungrouped dataNCERT §13.4, §13.4.111 min1 sim 04Mean deviation for discrete frequenciesNCERT §13.4.27 min 05Mean deviation for class intervalsNCERT §13.4.210 min1 sim 06From absolute values to squaresNCERT §13.4.3, §13.57 min 07Variance and standard deviationNCERT §13.5, §13.5.19 min1 sim 08Standard deviation of frequency distributionsNCERT §13.5.2, §13.5.36 min 09Shortcut method for varianceNCERT §13.5.46 min 10Shifting, scaling and correcting dataNCERT § "Miscellaneous Examples"11 min1 sim 11Chapter reviewMust-know facts, traps and formulas15 min

Simulations

4 in this chapter

Where is the total distance least?In: Mean deviation for ungrouped data Find the median class, then the medianIn: Mean deviation for class intervals Squares on the deviationsIn: Variance and standard deviation Shift the scores, stretch the scoresIn: Shifting, scaling and correcting data