JEE Main 2020 · MathsNumerical answerNumerical valueEasyCalculation

JEE Main 4 September 2020, Shift 2, Maths Q71

Question 71 of 75 in this shift, Maths question 21 of 25.

If the variance of the following frequency distribution : Class : 10-20 20-30 30-40 Frequency : 2

x

2 is 50, then

x

is equal to ________.

Official answer

4.00

NTA final key (Sep 2020).

Chapter: Statistics
Topic: Variance and SD
Idea tested: Finding Unknown Frequency via Variance

Same idea in other shifts

Asked 3× in all

6 Apr 2023, Shift 2 · Q29If the mean and variance of the frequency distribution $x_i$ : 2, 4, 6, 8, 10, 12, 14, 16 $f_i$ : 4, 4, $\alpha$ , 15, 8, $\beta$ , 4, 5 are 9…MediumNumerical valueHas a figure
13 Apr 2023, Shift 1 · Q29Let the mean of the data | $x$ | 1 | 3 | 5 | 7 | 9 | | Frequency ( $f$ ) | 4 | 24 | 28 | $\alpha$ | 8 | be 5. If $m$ and $\sigma^2$ are…MediumNumerical value

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.