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Friday, 9 October

JEE Main Maths · Statistics

Finding Unknown Observations from Mean and Variance

Finding Unknown Observations from Mean and Variance (Statistics) was asked 8 times in 8 JEE Main shifts, 2021–2026, out of the 42 shifts Lumi analysed. 2 of the 8 had a numerical answer.

Times asked
8
in 8 shifts
Years
2021–2026
Usual format
Single correct
Calculation
Pattern
Asked most years
repeats across shifts

How it is asked

  • Find unknown data from mean and variance
  • Find unknown observations from mean and variance

Difficulty

Easy 0Medium 8Hard 0

Where it sits

Chapter: Statistics. Topic: Variance and SD, 27 questions over 10 ideas.

Other repeat ideas in this topic

Every time it came

All 8 questions

Newest first, each with its options and official answer.

  1. 6 Apr 2026, Shift 2 · Q8Let the mean and the variance of seven observations 2,4,α,8,β,12,142, 4, \alpha, 8, \beta, 12, 14, α<β\alpha<\beta, be 8 and 16 respectively. Then the…MediumSingle correct
  2. 2 Apr 2025, Shift 2 · Q8If the mean and the variance of 6, 4, a, 8, b, 12, 10, 13 are 9 and 9.25 respectively, then a+b+aba+b+ab is equal to :MediumSingle correct
  3. 3 Apr 2025, Shift 2 · Q9Let the Mean and Variance of five observations x1=1,x2=3,x3=a,x4=7x_1 = 1, x_2 = 3, x_3 = a, x_4 = 7 and x5=b, a>bx_5 = b,\ a > b, be 5 and 10 respectively. Then…MediumSingle correct
  4. 4 Apr 2025, Shift 2 · Q8Let the mean and the standard deviation of the observation 2, 3, 3, 4, 5, 7, a, b be 4 and 2\sqrt{2} respectively. Then the mean…MediumSingle correct
  5. 29 Jan 2024, Shift 1 · Q30If the mean and variance of the data 65,68,58,44,48,45,60,α,β,6065, 68, 58, 44, 48, 45, 60, \alpha, \beta, 60 where α>β\alpha>\beta, are 56 and 66.2 respectively,…MediumNumerical value
  6. 31 Jan 2024, Shift 2 · Q18Let the mean and the variance of 6 observations a,b,68,44,48,60a, b, 68, 44, 48, 60 be 55 and 194, respectively. If a>ba>b, then a+3ba+3b isMediumSingle correct
  7. 29 Jun 2022, Shift 1 · Q20Let the mean and the variance of 5 observations x1,x2,x3,x4,x5x_1, x_2, x_3, x_4, x_5 be 245\frac{24}{5} and 19425\frac{194}{25} respectively. If the mean…MediumSingle correct
  8. 3 Aug 2021, Shift 2 · Q88The mean and variance of 7 observations are 7 and 18 respectively. If 5 of the observations are 2, 4, 10, 11, 13 and the remaining…MediumNumerical value