-

Buy RRB - ALP & Technicians Practice test pack

Question - 1

If \(f\left( x \right) =\begin{cases} k{ x }^{ 2 },0 is a probability density function then the value of k is.

  • A 1/3
  • B 1/6
  • C 1/9
  • D 1/12

Question - 2

If \(f\left( x \right) =\frac { A }{ \pi } \frac { 1 }{ 16+{ x }^{ 2 } } ,-\infty is a p.d.f of a continuous random variable X, then the value of A is.

  • A 16
  • B 8
  • C 4
  • D 1

Question - 3

A random variable X has the following probability distribution

X 0 1 2 3 4 5
P(X-x) 1/4 2a 3a 4a 5a 1/4

Then \(P\left( 1\le x\le 4 \right) \) is...

  • A 10/21
  • B 2/7
  • C 1/14
  • D 1/2

Question - 4

X is a discrete random variable which takes the values 0,1,2 and P(X =0) = 144 / 169, P(X=1) = 1/169 then the value of P(X=2) is.

  • A 145/169
  • B 24/169
  • C 2/169
  • D 143/169

Question - 5

Given E(X +c) = 8 and E (X –c) = 12 then the value of c is.

  • A -2
  • B 4
  • C -4
  • D 2

Question - 6

X is a random variable taking the values 3,4 and 12 with probabilities 1/3, 1/4 and 5 / 12 . Then E(X) is.

  • A 5
  • B 6
  • C 7
  • D 3

Question - 7

Variance of the random variable X is 4.  Its mean is 2 . Then E(X²) is

  • A 2
  • B 4
  • C 6
  • D 8

Question - 8

In 5 throws of a die, getting 1 or 2 is a success. The mean number of successes is

  • A 5/3
  • B 3/5
  • C 5/9
  • D 9/5

Question - 9

The mean of binomial distribution is 5 and its standard deviation is 2. Then the value of n and p are.

  • A \(\left( \frac { 4 }{ 5 } ,25 \right) \)
  • B \(\left( 25,\frac { 4 }{ 5 } \right) \)
  • C \(\left( \frac { 1 }{ 5 } ,25 \right) \)
  • D \(\left( 25,\frac { 1 }{ 5 } \right) \)

Question - 10

If the mean and standard deviation of a binomial distribution are 12 and 2 respectively. Then the value of  its parameter p is.

  • A 1/2
  • B 1/3
  • C 2/3
  • D 1/4