Verified Solution • 2025–26 Session moderate

QJEEM17Mac6cd: JEE Main 2017 Mathematics - Class 11 JEEM17Mac6cd Solution: The sum of 100 observations and the sum of their squares are…

The sum of 100 observations and the sum of their squares are 400 and 2475, respectively. Later on, three observations, 3, 4 and 5, were found to be incorrect. If the incorrect observations are omitted, then the variance of the remaining observations is :

Multiple Choice Options

  • A 8.25
  • B 8.5
  • C 8
  • D 9

Step-by-Step Verified Solution

We have

∑i=1100xi=400

∑i=1100xi2=2425

The variance of the remaining observations is

σ2=∑xi2N−(∑xiN)2

⇒242597−(38897)2

⇒242597−16

⇒2425−155297=87397=9

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