Random Variables and its Probability Distributions

IMPORTANT

Random Variables and its Probability Distributions: Overview

This topic covers concepts such as Probability Distribution of a Random Variable, Random Variable, Mean/Expectation of a Random Variable, Variance of a Random Variable, and Standard Deviation of a Random Variable.

Important Questions on Random Variables and its Probability Distributions

MEDIUM
IMPORTANT

Following is the distribution function Fx of a discrete random variable X

x123456F(x)0.20.370.480.620.851

Find P(X5|X>3).

HARD
IMPORTANT

In a game, a man wins Rs. 100 if he gets 5 or 6 on a throw of a fair die and loses Rs. 50 for getting any other number on the die. If he decides to throw the die either till he gets a 5 or a 6 or to a maximum of three throws, then his expected gain/loss (in rupees) is:

EASY
IMPORTANT

Three balanced coins are tossed simultaneously. If X denotes the number of heads, find the probability distribution of X.

HARD
IMPORTANT

Product of the variance and standard deviation of the random variable X whose probability
distribution is given below

x 0 1 2 3
PX=x 18 38 38 18

 

MEDIUM
IMPORTANT

Let the p.m.f. of a random variable X be P(x)=3-x10  for  x=-1,0,1,2 and 0 otherwise. Then value of EX is

HARD
IMPORTANT

If x is a random variable with probability distribution px=k=(k+1)C2k, k=0, 1, 2, 3,., then C=

EASY
IMPORTANT

If the mean and variance of a binomial variable X are 2.4 and 1.44 respectively, find the parameter n of the distribution X. (Binomial).

HARD
IMPORTANT

A cubical die is thrown. Find the mean and variance of x, giving the number on the face shows up.

MEDIUM
IMPORTANT

The mean and variance of a binomial distribution are 4 and 3 respectively. Fix the distribution and find PX1.

EASY
IMPORTANT

Following is the distribution function F (x) of a discrete r.v. X

x123456F(x)0.20.370.480.620.851

Find P(X5|X>3).

  

HARD
IMPORTANT

Let X have p.m.f. p(x)=k·x2;x=1,2,3,4

=0; otherwise.

Find variance of X.

HARD
IMPORTANT

The p.m.f. for X= number of major defects in a randomly selected appliance of a certain type is:

X=x 0 1 2 3 4
P(x) 0.08 0.15 0.45 0.27 0.05

Find the standard deviation of X

HARD
IMPORTANT

A r.v. X has the following probability distribution :

X=x -2 -1 0 1 2 3
P(x) 0.1 k 0.2 2k 0.3 k

Find the value of k and calculate mean and variance of X

HARD
IMPORTANT

The p.m.f. of a r.v. X is

P(x)=115, for x=1,2,,14,15
        =0                otherwise.

Find Var(X).

MEDIUM
IMPORTANT

The probability distribution of a discrete random variable X is

X=x      1 2 3 4 5 6
PX=x k 2k 3k 4k 5k 6k

Determine the value of k.

HARD
IMPORTANT

A random variable X, has the probability distribution as given below. Let E=X|Xis prime number and F=XX<4, then PEF=

X 1 2 3 4 5 6 7 8
PX K 2K K2 2K2 5K2 K K 2K

 

MEDIUM
IMPORTANT

Following is the distribution function Fx of a discrete r.v. X

x123456F(x)0.20.370.480.620.851

Find the probability distribution of X.

  

EASY
IMPORTANT

A random variable X has the following probability distribution

x 0 1 2 3 4 5 6
P(x) k 3k 5k 7k 9k 11k 13k

Find p(x>2)+p(0<x<4).

MEDIUM
IMPORTANT

Obtain the probability distribution of the number of sixes in two tosses of a fair die.

MEDIUM
IMPORTANT

Determine k such that the following function is a probability mass function.

P(x)=k4x, x=0,1,2,3,4, k>00, otherwise