JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD

JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD B.Tech III PROBABILITY AND STATISTICS Previous Question Paper (February - 2022 - R15)

B.Tech | III | I | R15 | February - 2022

Answer PaperPaper Code: 125CVMaximum Marks: 75Time: 3 hours

Answer any five questions

All questions carry equal marks

Main

115 marks
a

A random variable X has the pdf

f(x) = ax3, 0 ≤ x ≤ 1; 0 elsewhere
. Determine (i) a and (ii)
P(X > 1/2)
.

7 marks

Answer

(i) Since f(x) is a probability density function, the total area under the curve must equal 1:

∫[0 to 1] ax3 dx = 1

Integrating the function:

a [x4 / 4] from 0 to 1 = 1
a(1/4 - 0) = 1
a = 4

(ii) To find P(X > 1/2):

P(X > 1/2) = ∫[1/2 to 1] 4x3 dx
= [x4] from 1/2 to 1
= 14 - (1/2)4 = 1 - 1/16 = 15/16 = 0.9375
b

The first four central moments of a distribution are 0, 2.5, 0.7 and 18.75. Compute β1 and β2.

8 marks

Answer

Given the central moments: μ1 = 0, μ2 = 2.5, μ3 = 0.7, and μ4 = 18.75.

The coefficient of skewness β1 is defined as:

β1 = μ32 / μ23
β1 = (0.7)2 / (2.5)3 = 0.49 / 15.625 = 0.03136

The coefficient of kurtosis β2 is defined as:

β2 = μ4 / μ22
β2 = 18.75 / (2.5)2 = 18.75 / 6.25 = 3
215 marks
a

If 30% of items from a factory are defective, find the probability that at least two are defective in a sample of 8.

6 marks

Answer

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b

Find the moment generating function of Poisson distribution and hence find its mean.

9 marks

Answer

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3

The joint probability mass function of the random variables X and Y is given by

f(x,y) = k(3x+5y), x=1,2,3; y=0,1,2
. Find (a) k (b)
P(X≤2, Y=2)
(c)
FX(2)
(d)
P(X<3, Y≤2)
and (e)
FY(2)
.

15 marks

Answer

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4

From the following data, calculate the correlation coefficient and obtain the two regression lines.

X123456789
Y9810121113141615
15 marks

Answer

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515 marks
a

A population consists of the four numbers 1, 5, 6, 8. Consider all possible samples of size 2 that can be drawn without replacement. Find the population mean and standard deviation.

7 marks

Answer

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b

Find the mean and standard deviation of the sampling distribution of means.

8 marks

Answer

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6

A manufacturer of electronic equipment subjects two competing brands of transistors to an accelerated performance test. If 45 of 180 transistors of the first kind and 34 of 120 transistors of the second kind fail the test, what can be concluded at the level of significance of 0.05, about the difference between the corresponding sample proportions.

15 marks

Answer

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7

Derive the formula for the probability distribution density function of the waiting time distribution.

15 marks

Answer

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815 marks
a

For a first order stationary random process, show that the mean is constant.

7 marks

Answer

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b

Show that random process

X(t) = cos(ωt + θ)
, where θ is uniformly distributed in
[-π, π]
, is stationary.

8 marks

Answer

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About this paper

This page contains the question paper of PROBABILITY AND STATISTICS from JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD for B.Tech PTM III I, February - 2022, R15.

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