A pair of dice numbered 1, 2, 3, 4, 5, 6 of a six-sided die and 1, 2, 3, 4 of a four-sided die is rolled and the sum is determined. Let the random variable X denote this sum. Then the number of elements in the inverse image of 7 is

(a)

1

(b)

2

(c)

3

(d)

4

A random variable X has binomial distribution with n = 25 and p = 0.8 then standard deviation of X is

(a)

6

(b)

4

(c)

3

(d)

2

Let X represent the difference between the number of heads and the number of tails obtained when a coin is tossed n times. Then the possible values of X are

(a)

i + 2n, i = 0,1,2... n

(b)

2i- n, i = 0,1,2... n

(c)

n - i, i = 0,1,2... n

(d)

2i + 2n, i = 0, 1, 2...n

If the function \(f(x)=\frac { 1 }{ 12 } \) for a < x < b, represents a probability density function of a continuous random variable X, then which of the following cannot be the value of a and b?

(a)

0 and 12

(b)

5 and 17

(c)

7 and 19

(d)

16 and 24

If X is a binomial random variable with expected value 6 and variance 2.4, then P(X = 5) is 

(a)

\(\left( \frac { 10 }{ 5 } \right) \left( \frac { 3 }{ 5 } \right) ^{ 6 }\left( \frac { 2 }{ 5 } \right) ^{ 4 }\) 

(b)

\(\left( \frac { 10 }{ 5 } \right) \left( \frac { 3 }{ 5 } \right) ^{ 10 }\)

(c)

\(\left( \frac { 10 }{ 5 } \right) { \left( \frac { 3 }{ 5 } \right) }^{ 4 }\left( \frac { 2 }{ 5 } \right) ^{ 6 }\)

(d)

\(\left( \frac { 10 }{ 5 } \right) \left( \frac { 3 }{ 5 } \right) ^{ 5 }\left( \frac { 2 }{ 5 } \right) ^{ 5 }\)