JEE Maths
JEEMathsSets & StatisticsClass 11

I keep getting “Measures of spread” questions wrong in Sets & Statistics. What's the trap?

thinking two data sets with the same mean must be alike.

The usual trap: thinking two data sets with the same mean must be alike. How to avoid it: same mean, different spread — the standard deviation tells them apart. Go back to the definition — standard deviation measures how far the data typically lie from the mean — small means tightly clustered, large means spread out.

Key point

Measures of spread

Common mistake

thinking two data sets with the same mean must be alike.

Memory tip

same mean, different spread — the standard deviation tells them apart.

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