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Previous Year Question Paper

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

June 2023AIMLSEMESTER-3
June 2023
Max Marks: 70
Duration: 3 Hours
Instructions:

Attempt any five questions.

All questions carry equal marks.

Q.1
a)Unit 2

Define continuous random variable. Also show that E(X₁X₂...Xₙ)=E(X₁)E(X₂)...E(Xₙ).

b)Unit 1

Define non-central and central moments. Also, show that V(2X+3)=4V(X).

Q.2
a)Unit 1

Show that Poisson distribution is a limiting case of binomial distribution under the case n→∞, p→0 and np=m.

b)Unit 2

Define gamma distribution. If X follows exponential distribution with parameter λ, then obtain its mean and variance.

Q.3
a)Unit 2

If X~N(μ,σ²), then show that φₓ(t)=e^(iμt-½t²σ²).

b)Unit 2

A large number of measurement is normally distributed with a mean 65.5 cm and S.D. of 6.2 cm. Find the percentage of measurement that fall between 54.8 cm and 68.8 cm.

Q.4
a)Unit 4

Write down merits and demerits of measure of central tendency. Find the median for the given data.

b)Unit 1

Show that sum of two independent random variables follows normal distribution.

Q.5
a)Unit 5

Using method of Least squares, find the curve y=ax+ax² that best fit the given data.

b)Unit 6

Out of 8000 graduates in a town, 800 are females, out of 1600 graduate employees, 120 are females. Use χ² test to determine if any distinction is made in appointment on the basis of sex. The value of χ² for 1 degree of freedom at 5% level is 3.841.

Q.6
a)Unit 4

Define Poisson distribution and obtain its mean and variance.

b)Unit 2

Define gamma distribution with parameter λ and obtain its mean, variance, and characteristic function.

Q.7
a)Unit 4

What do you mean by measure of kurtosis? Obtain β₁ and β₂ for the function: f(x)=y₀x(2-x); 0≤x≤2.

b)Unit 4

Define Karl Pearson's correlation coefficient and obtain the correlation coefficient for the given data.

Q.8
a)Unit 4

Find the rank correlation coefficient for the given data.

b)Unit 4

Define binomial distribution and derive its moment generating function. Hence, obtain its mean and variance.