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#### Term 3 Probability Book Back Questions

9th Standard

Reg.No. :
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Maths

Time : 00:45:00 Hrs
Total Marks : 30
7 x 1 = 7
1. A number between 0 and 1 that is used to measure uncertainty is called

(a)

Random variable

(b)

Trial

(c)

Simple event

(d)

Probability

2. A random experiment contains

(a)

Atleast one outcome

(b)

At least two outcomes

(c)

Atmost one outcome

(d)

Atmost two outcomes

3. The probability of all possible outcomes of a random experiment is always equal to

(a)

One

(b)

Zero

(c)

Infinity

(d)

All of the above

4. If A is any event in S then its complement P(A′) is equal to

(a)

1

(b)

0

(c)

1-A

(d)

1-P(A)

5. Which of the following cannot be taken as probability of an event?

(a)

0

(b)

0.5

(c)

1

(d)

-1

6. A collection of one or more outcomes of an experiment is called

(a)

Event

(b)

Outcome

(c)

Sample point

(d)

None of the above

7. A letter is chosen at random from the word “STATISTICS”. The probability of getting a vowel is

(a)

$\frac { 1 }{ 10 }$

(b)

$\frac { 2 }{ 10 }$

(c)

$\frac { 3 }{ 10 }$

(d)

$\frac { 4 }{ 10 }$

8. 7 x 2 = 14
9. You are walking along a street. If you just choose a stranger crossing you, what is the probability that his next birthday will fall on a sunday?

10. What is the probability of drawing a King or a Queen or a Jack from a deck of cards?

11. When two coins are tossed, what is the probability that two heads are obtained?

12. A manufacturer tested 7000 LED lights at random and found that 25 of them were defective. If a LED light is selected at random, what is the probability that the selected LED light is a defective one.

13. In a football match, a goalkeeper of a team can stop the goal, 32 times out of 40 attempts tried by a team. Find the probability that the opponent team can convert the attempt into a goal.

14. A company manufactures 10000 Laptops in 6 months. In that 25 of them are found to be defective. When you choose one Laptop from the manufactured, what is the probability that selected Laptop is a good one.

15. If a probability of a player winning a particular tennis match is 0.72. What is the probability of the player loosing the match?

16. 3 x 3 = 9
17. When a dice is rolled, find the probability to get the number greater than 4?

18. In an office, where 42 staff members work, 7 staff members use cars, 20 staff members use two-wheelers and the remaining 15 staff members use cycles. Find the relative frequencies.

19. The probability that it will rain tomorrow is $\\ \frac { 91 }{ 100 }$. What is the probability that it will not rain tomorrow?