JEE Main 2019MathematicsStatisticsMediumMCQ

JEE Main 2019 — Statistics Question with Solution

JEE Main 2019 (09 Jan Shift 1)

Question

5 students of a class have an average height 150 cm and variance 18 cm2. A new student, whose height is 156 cm, joined them. The variance in cm2 of the height of these six students is:

Choose an option

Show full solutionCorrect option: D
Correct answer
D20

Step-by-step explanation

Let 1st 5 students are

x1, x2, x3 ,x4 and x5

∴18=Ex2-Ex2

=x12+x22+x32+x42+x525-1502

⇒x12+x22+x32+x42+x52=112590

∴ new variance  =x12+x22+....+x52+15626-(151)2 Since new mean=150×5+1566=151

=112590+243366-22801

=20

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About this question

This is a previous-year question from JEE Main 2019, covering the Statistics chapter of Mathematics. PrepSharp catalogues every PYQ from JEE Main with a verified answer key and step-by-step solution prepared by IIT alumni — so you can search by chapter, topic or year and revise efficiently.