NCERT Mathematics Class 9 Exemplar Ch 14 Statistics and Probability Part 11
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Q.16. A company selected 4000 households at random and surveyed them to find out a relationship between income level and the number of television sets in a home. The information so obtained is listed in the following table:
Monthly income Number of Televisions/household (in Rs) | Number of Televisions/household | |||
0 | 1 | 2 | Above 2 | |
Find the probability:
(i) Of a household earning per year and having exactly one television.
(ii) Of a household earning and more per year and owning 2 televisions.
(iii) Of a household not having any television.
Answer: (i) (ii) (iii)
Q.17. Two dice are thrown simultaneously 500 times. Each time the sum of two numbers appearing on their tops is noted and recorded as given in the following table:
Sum | Frequency |
2 | 14 |
3 | 30 |
4 | 42 |
5 | 55 |
6 | 72 |
7 | 75 |
8 | 70 |
9 | 53 |
10 | 46 |
11 | 28 |
12 | 15 |
If the dice are thrown once more, what is the probability of getting a sum?
(i) 3?
(ii) More than 10?
(iii) Less than or equal to 5?
(iv) Between 8 and 12?
Answer: (i) (ii) (iii) (iv)