JEE Main 2023 · MathsNumerical answerNumerical valueMediumCalculation

JEE Main 13 April 2023, Shift 1, Maths Q29

Question 29 of 90 in this shift, Maths question 29 of 30, Section B.

Let 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 respectively the mean deviation about the mean and the variance of the data, then

\frac{3\alpha}{m+\sigma^2}

is equal to ________.

Official answer

NTA final key.

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
4 Sep 2020, Shift 2 · Q71If 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…EasyNumerical 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.