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Saturday, 31 October

JEE Main · Maths · Statistics

Finding Unknown Frequency via Variance

JEE Main asked Finding Unknown Frequency via Variance 3 times in 3 of the 108 shifts Lumi analysed, in 2020 and 2023. It belongs to Variance and SD, in Statistics (Maths). The longest wait between two years asking it was 3 years. In 2023 it came in more than one shift of the same year.

Updated 2026-10-24

Times asked
3
in 3 shifts
Years
2 of 8
First asked
2020
last in 2023
Pattern
Occasional
across the analysed shifts

Questions on this idea a shift, by year

2017–2026. Asked in 2020 and 2023. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift of 25 Maths questions.

00.10.20’170.08’200’210’220.14’230’240’250’26

Raw count: 2017: 0 in 1 shift · 2020: 1 in 12 shifts · 2021: 0 in 24 shifts · 2022: 0 in 24 shifts · 2023: 2 in 12 shifts · 2024: 0 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Shift by shift

Each square is one analysed shift, in date order. Open a filled one for that paper.

  • 20260 of 9
  • 20250 of 8
  • 20240 of 18
  • 20232 of 12
  • 20220 of 24
  • 20210 of 24
  • 20201 of 12
  • 20170 of 1

Asked in that shift More than once Not asked

How JEE Main framed it

Numerical value is the usual form. Skill tested: calculation.

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

Difficulty

Easy 1Medium 2Hard 0

3 of the 3 questions had a numerical answer.

Every question

All 3 questions

From the official JEE Main shift papers, newest first. Open one for the full question, the options and the official answer.

  1. 13 Apr 2023, Shift 1 · Q29Let the mean of the data | xx | 1 | 3 | 5 | 7 | 9 | | Frequency (ff) | 4 | 24 | 28 | α\alpha | 8 | be 5. If mm and σ2\sigma^2 are…MediumNumerical value
  2. 6 Apr 2023, Shift 2 · Q29If the mean and variance of the frequency distribution xix_i: 2, 4, 6, 8, 10, 12, 14, 16 fif_i: 4, 4, α\alpha, 15, 8, β\beta, 4, 5 are 9…MediumNumerical valueHas a figure
  3. 4 Sep 2020, Shift 2 · Q71If the variance of the following frequency distribution : Class : 10-20 20-30 30-40 Frequency : 2 xx 2 is 50, then xx is equal to…EasyNumerical value

Shifts: 4 Sep 2020, Shift 2, 6 Apr 2023, Shift 2, 13 Apr 2023, Shift 1.

Same topic

Other ideas in Variance and SD

Variance and SD has 20 ideas JEE Main has asked; 10 of them came up in more than one question. The 12 most asked are below.

Topic analysisChapter analysisStudy this chapterAll repeated ideas