Chapter 11: Probability Distributions - Online Test
Q1. If P(X = 0) = 1 − P(X = 1). If E(X)
= 3Var(X), then P(X = 0) is
Answer : Option D
Explaination / Solution:
Q2. If X
is a binomial random variable with expected value 6 and variance 2.4, then P(X
= 5) is
Answer : Option D
Explaination / Solution:
Q3.
The random variable x has
the probability density function
and E ( x )
= 7/12, then a and b are respectively
Answer : Option A
Explaination / Solution:
Q4.
Suppose that x takes on one of the values 0, 1, and 2. If for some constant k, P (X = i ) = k P ( X = i −1) for i = 1, 2 and P ( x = 0 ) = 1/7 , then the value of k is
Answer : Option B
Explaination / Solution:
Q5.
Which of
the following is a discrete random variable?
I. The
number of cars crossing a particular signal in a day.
II. The
number of customers in a queue to buy train tickets at a moment.
Answer : Option A
Explaination / Solution:
No Explaination.
Q6. If 
is a probability density function
of a random variable, then the value of a is
is a probability density function
of a random variable, then the value of a is
Answer : Option A
Explaination / Solution:
Q7.
The probability mass function of a random variable is
defined as:
Answer : Option D
Explaination / Solution:
Q8. Let X
have a Bernoulli distribution with mean 0.4, then the variance of (2X–3) is
Answer : Option D
Explaination / Solution:
Q9. If in 6 trials, X is a binomial variable which follows the relation 9P(X=4)
= P(X=2), then the probability of success is
Answer : Option B
Explaination / Solution:
Q10. A computer salesperson knows from his past
experience that he sells computers to one in every twenty customers who enter
the showroom. What is the probability that he will sell a computer to exactly
two of the next three customers?
Answer : Option A
Explaination / Solution:
