How to practice Probability and Statistics

Attempt a question, record the concept and assumptions, then check the available answer. Rework mistakes after revising the relevant concepts. Topic tags can overlap; review the question context.

Questions 1–10 of 17. Imported answers require independent review unless marked reviewed.

Topic practice 17 questionsPage 1 of 2

Question 38

Open question
ECMCQ2 marksNeeds review
Let X, N, Y and Z be random variables. The variables X and N are independent of each other. X is uniformly distributed between -1 and 1; N follows Normal distribution with zero mean and unity variance. Y and Z are defined as,

and

. Which of the following pairs represents the values of correlation between X and Y and that between X and Z?
Your answerChoose one option.

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Question 13

Open question
ECMCQ1 markNeeds review
A pot contains two red balls and two blue balls. Two balls are drawn from this pot randomly without replacement.
What is the probability that the two balls drawn have different colours?
Your answerChoose one option.

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Question 58

Open question
ECNAT2 marksNeeds review
Two fair dice (with faces labeled 1, 2, 3, 4, 5, and 6) are rolled. Let the random variable

denote the sum of the outcomes obtained.
The expectation of

is ______ (rounded off to two decimal places).

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Question 33

Open question
ECNAT1 markNeeds review
Suppose X and Y are independent and identically distributed random variables that are distributed uniformly in the interval [0,1]. The probability that X ≥ Y is ______ .

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Question 36

Open question
ECMCQ2 marksNeeds review
A random variable

, distributed normally as

, undergoes the transformation

, given in the figure. The form of the probability density function of

is
(In the options given below,

,

,

are non-zero constants and

is piece-wise continuous function)
Diagram for Electronics and Communication Engineering question 36

Your answerChoose one option.

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Question 3

Open question
ECMCQ1 markNeeds review
Two continuous random variables

and

are related as

Let

and

denote the variances of

and

, respectively. The variances are related as
Your answerChoose one option.

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Question 27

Open question
ECMCQ2 marksNeeds review
A box contains the following three coins. I. A fair coin with head on one face and tail on the other face. II. A coin with heads on both the faces. III. A coin with tails on both the faces.
A coin is picked randomly from the box and tossed. Out of the two remaining coins in the box, one coin is then picked randomly and tossed. If the first toss results in a head, the probability of getting a head in the second toss is
Your answerChoose one option.

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Question 51

Open question
ECNAT2 marksNeeds review
In a high school having equal number of boy students and girl students, 75% of the students study Science and the remaining 25% students study Commerce. Commerce students are two times more likely to be a boy than are Science students. The amount of information gained in knowing that a randomly selected girl student studies Commerce (rounded off to three decimal places) is ______ bits.

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Question 22

Open question
ECNAT1 markNeeds review
A binary random variable

takes the value +2 or −2. The probability

. The value of

(rounded off to one decimal place), for which the entropy of

is maximum, is ______.

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Question 25

Open question
ECNAT1 markNeeds review
The two sides of a fair coin are labelled as 0 and 1. The coin is tossed two times independently. Let

and

denote the labels corresponding to the outcomes of those tosses. For a random variable

, defined as

, the expected value

(rounded off to two decimal places) is ______.

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