# NCERT Class 12-Mathematics: Chapter – 13 Probability Part 5 (For CBSE, ICSE, IAS, NET, NRA 2022)

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Question 14:

Let A and B be two events such that , and .

Then equals

(A)

(B)

(C)

(D)

Answer:

The correct answer is (C) .

Question 15:

If A and B are independent events such that and , then which of the following is not correct?

(A) and are mutually exclusive

(B) and are independent

(C) and are independent

(D) and are independent

Answer:

The correct answer is (A)

Question 16:

Let be a discrete random variable. The probability distribution of is given below:

Then E (X) is equal to

(A)

(B)

(C)

(D)

Answer:

The correct answer is (B) .

Question 17:

Let be a discrete random variable assuming values with probabilities , respectively. Then variance of is given by

(A)

(B)

(C)

(D)

Answer:

The correct answer is (C) .

## Fill in the Blanks in Examples 18 and 19

Question 18:

If A and B are independent events such that and ________

Answer:

Question 19:

If and are independent events then ________

Answer:

.

### State Whether Each of the Statement in Examples 20 to 22 is True or False

Question 20:

Let A and B be two independent events. Then

Answer: False

Because when events A and B are independent.

Question 21:

Three events A, B and C are said to be independent if .

Answer: False

Reason is that A, B, C will be independent if they are pairwise independent and .

Question 22:

One of the condition of Bernoulli trials is that the trials are independent of each other.

Answer: True