Statistics Questions

MathematicsStatistics25 Questions Found

MathematicsVariance and Standard DeviationJEE Main 2012Easy

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Let $x_{1}, x_{2}, \dots, x_{n}$ be n observations, and let $\overset{x}{ˉ}$ be their arithmetic mean and $σ^{2}$ be the variance. Statement-1 : Variance of $2 x_{1}, 2 x_{2}, \dots, 2 x_{n}$ is $4 σ^{2}$ Statement-2 : Arithmetic mean $2 x_{1}, 2 x_{2}, \dots, 2 x_{n}$ is $4 \overset{x}{ˉ}$ .

(A)

Statement-1 is false, Statement-2 is true.

(B)

Statement-1 is true, statement-2 is true; statement-2 is a correct explanation for Statement-1.

(C)

Statement-1 is true, statement-2 is true; statement-2 is not a correct explanation for Statement-1.

(D)

Statement-1 is true, statement-2 is false.

Answer:D

MathematicsMeasures of DispersionJEE Main 2013Easy

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All the students of a class performed poorly in Mathematics. The teacher decided to give grace marks of 10 to each of the students. Which of the following statistical measures will not change even after the grace marks were given ?

(A)

mean

(B)

median

(C)

mode

(D)

variance

Answer:D

MathematicsMeasures of DispersionJEE Main 2014Easy

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The variance of first 50 even natural numbers is

(A)

437

(B)

437/4

(C)

833/4

(D)

833

Answer:D

MathematicsMeasures of Central Tendency (Mean, Median, Mode)JEE Main 2015Easy

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The mean of the data set comprising of 16 observations is 16. If one of the observation valued 16 is deleted and three new observations valued 3, 4 and 5 are added to the data, then the mean of the resultant data, is:

(A)

15.8

(B)

14.0

(C)

16.8

(D)

16.0

Answer:B

MathematicsMeasures of DispersionJEE Main 2016Easy

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If the standard deviation of the numbers 2, 3, a and 11 is 3.5, then which of the following is true?

(A)

3a² - 34a + 91 = 0

(B)

3a² - 23a + 44 = 0

(C)

3a² - 26a + 55 = 0

(D)

3a² - 32a + 84 = 0

Answer:D