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Previous Year Question Paper

AI/AL/CD-302 (GS) – Introduction to Probability and Statistics

December 2024AIMLSEMESTER-3
December 2024
Max Marks: 70
Duration: 3 Hours
Instructions:

Attempt any five questions.

All questions carry equal marks.

Q.1
a)Unit 1

If X is a continuous random variable and k is a constant. Then prove that Var(X+k)=Var(X) and Var(kX)=k²Var(X).

b)Unit 1

State and Prove Chebyshev's inequality.

Q.2
a)Unit 1

A random variable X is defined as the sum of the numbers on the faces when two dice are thrown. Find the mean of X.

b)Unit 2

Explain Exponential and Gamma densities with properties.

Q.3
Unit 2

The probability density function of a random variable X is f(x)=sin(x)/2 for 0≤x≤π and 0 elsewhere. Find the mean, mode and median of a distribution and also find the probability between 0 and π/2.

Q.4
a)Unit 3

Define Bivariate distribution and explain their properties.

b)Unit 3

If first box contains 2 black, 3 red, 1 white balls; Second box contains 1 black, 1 red, 2 white balls; Third box contains 5 black, 3 red, 4 white balls. Of these a box is selected at random. From it a red ball is randomly drawn. If the ball is red, find the probability that it is from second box.

Q.5
a)Unit 4

The values of μ₁, μ₂, μ₃ and μ₄ are 0, 9.2, 3.6 and 1.22 respectively. Find out the Skewness and Kurtosis of the distribution.

b)Unit 2

The mean and standard deviation of a normal variable are 8 and 4 respectively. Find: P(5≤X≤10) and P(X≥5).

Q.6
a)Unit 4

Average number of accidents on any day on a national highway is 1.6. Determine the probability that the number of accidents are:

i) at least one

ii) at most one.

b)Unit 4

Define correlation. Explain types of correlation and methods of studying correlation.

Q.7
a)Unit 5

Fit a Straight line for the given data.

b)Unit 5

A sample of 400 items is taken from a population whose standard deviation is 10. The mean of the sample is 40. Test whether the sample has come from a population with mean 38. Also calculate 95% confidence interval for the population.

Q.8
a)Unit 6

Define Chi-Square test of goodness of fit. Explain the conditions for Chi-Square test.

b)Unit 4

Calculate coefficient of correlation from the given data.