JEE Main 2021 · MathsNumerical answerNumerical valueMediumMulti-step

JEE Main 26 February 2021, Shift 2, Maths Q85

Question 85 of 90 in this shift, Maths question 25 of 30, Section B.

Let

X_1, X_2, \ldots, X_{18}

be eighteen observations such that

\sum_{i=1}^{18}(X_i-\alpha)=36

and

\sum_{i=1}^{18}(X_i-\beta)^2=90

, where

\alpha

and

\beta

are distinct real numbers. If the standard deviation of these observations is

1

, then the value of

|\alpha-\beta|

is __________.

Official answer

NTA final key.

Chapter: Statistics
Topic: Variance and SD
Idea tested: Minimum Sum of Squared Deviations

Same topic in other shifts

All Variance and SD questions

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Question text from the official JEE Main paper published by NTA; answer from the final answer key. Chapter, topic and idea tags, difficulty and skill are Lumi’s. Lumi analyses 108 of the 174 JEE Main shifts held from 2017 to 2026.