“Choosing to be positive and having a grateful attitude is going to determine how you’re going to live your life.” – **Joel Osteen**

# Lecture - 2 Chapter 16 Probability

NCERT Exercise 16.1 |

In each of the following Exercises 1 to 7, describe the sample space for the indicated experiment.

**1.** A coin is tossed three times.

**2.** A die is thrown two times.

**3.** A coin is tossed four times.

**4.** A coin is tossed and a die is thrown.

**5.** A coin is tossed and then a die is rolled only in case a head is shown on the coin.

**6.** 2 boys and 2 girls are in Room X, and 1 boy and 3 girls in Room Y. Specify the sample space for the experiment in which a room is selected and then a person.

**7.** One die of red colour, one of white colour and one of blue colour are placed in a bag. One die is selected at random and rolled, its colour and the number on its uppermost face is noted. Describe the sample space.

**8.** An experiment consists of recording boy–girl composition of families with 2 children. **(i)** What is the sample space if we are interested in knowing whether it is a boy or girl in the order of their births?**(ii)** What is the sample space if we are interested in the number of girls in the family?

**9.** A box contains 1 red and 3 identical white balls. Two balls are drawn at random in succession without replacement. Write the sample space for this experiment.

**10.** An experiment consists of tossing a coin and then throwing it second time if a head occurs. If a tail occurs on the first toss, then a die is rolled once. Find the sample space.

**11.** Suppose 3 bulbs are selected at random from a lot. Each bulb is tested and classified as defective (D) or non – defective(N). Write the sample space of this experiment.

**12.** A coin is tossed. If the out come is a head, a die is thrown. If the die shows up an even number, the die is thrown again. What is the sample space for the experiment?

**13.** The numbers 1, 2, 3 and 4 are written separately on four slips of paper. The slips are put in a box and mixed thoroughly. A person draws two slips from the box, one after the other, without replacement. Describe the sample space for the experiment.

**14.** An experiment consists of rolling a die and then tossing a coin once if the number on the die is even. If the number on the die is odd, the coin is tossed twice. Write the sample space for this experiment.

**15.** A coin is tossed. If it shows a tail, we draw a ball from a box which contains 2 red and 3 black balls. If it shows head, we throw a die. Find the sample space for this experiment.

**16.** A die is thrown repeatedly until a six comes up. What is the sample space for this experiment?