Question 1

What is the probability of an impossible event?

Accepted Answer

The probability of an impossible event is always 0. By definition, an event that cannot occur has zero favorable outcomes, making its probability zero.

Question 2

What is the probability of a sure (or certain) event?

Accepted Answer

The probability of a sure or certain event is always 1, because the event is guaranteed to happen and all outcomes are favorable.

Question 3

For any event E, which of the following relations is true?

Accepted Answer

The probability of any event E lies between 0 and 1 inclusive, expressed mathematically as 0 ≤ P(E) ≤ 1.

Question 4

If P(E) = 0.05, what is the probability of 'not E'?

Accepted Answer

We know that P(E) + P(not E) = 1. Therefore, P(not E) = 1 - P(E) = 1 - 0.05 = 0.95.

Question 5

Which of the following cannot be the probability of an event?

Accepted Answer

Probability can never be negative. Since -1.5 is less than 0, it cannot be a valid probability.