Advertisements
Advertisements
प्रश्न
To know the opinion of the students about the subject statistics, a survey of 200 students was conducted. The data is recorded in the following table.
Opinion | Number of students |
like | 135 |
dislike | 65 |
Find the probability that a student chosen at random
(i) likes statistics, (ii) does not like it
उत्तर
Total number of students = 135 + 65 = 200
(i) Number of students liking statistics = 135
`"P(Students liking statistics) "=135/200=27/40`
(ii) Number of students who do not like statistics = 65
`"P(Students not liking statistics) "=65/200=13/40`
APPEARS IN
संबंधित प्रश्न
A coin is tossed 1000 times with the following frequencies:
Head: 455, Tail: 545
Compute the probability for each event.
Three coins are tossed simultaneously 100 times with the following frequencies of different outcomes:
Outcome: | No head | One head | Two heads | Three heads |
Frequency: | 14 | 38 | 36 | 12 |
If the three coins are simultaneously tossed again, compute the probability of:
(i) 2 heads coming up.
(ii) 3 heads coming up.
(iii) at least one head coming up.
(iv) getting more heads than tails.
(v) getting more tails than heads.
Following table shows the birth month of 40 students of class IX.
Jan | Feb | March | April | May | June | July | Aug | Sept | Oct | Nov | Dec |
3 | 4 | 2 | 2 | 5 | 1 | 2 | 5 | 3 | 4 | 4 | 4 |
A company selected 2400 families at random and survey them to determine a relationship between income level and the number of vehicles in a home. The information gathered is listed in the table below:
Monthly income: (in Rs) |
Vehicles per family | |||
0 | 1 | 2 | Above 2 | |
Less than 7000 7000-10000 10000-13000 13000-16000 16000 or more |
10 0 1 2 1 |
160 305 535 469 579 |
25 27 29 29 82 |
0 2 1 25 88 |
If a family is chosen, find the probability that family is:
(i) earning Rs10000-13000 per month and owning exactly 2 vehicles.
(ii) earning Rs 16000 or more per month and owning exactly 1 vehicle.
(iii) earning less than Rs 7000 per month and does not own any vehicle.
(iv) earning Rs 13000-16000 per month and owning more than 2 vehicle.
(v) owning not more than 1 vehicle
(vi) owning at least one vehicle.
The following table gives the life time of 400 neon lamps:
Life time (in hours) |
300-400 | 400-500 | 500-600 | 600-700 | 700-800 | 800-900 | 900-1000 |
Number of lamps: | 14 | 56 | 60 | 86 | 74 | 62 | 48 |
A bulb is selected of random, Find the probability that the the life time of the selected bulb is:
(i) less than 400
(ii) between 300 to 800 hours
(iii) at least 700 hours.
The probability of a certain event is
In a medical examination of students of a class, the following blood groups are recorded:
Blood group | A | AB | B | O |
Number of students | 10 | 13 | 12 | 5 |
A student is selected at random from the class. The probability that he/she has blood group B, is:
80 bulbs are selected at random from a lot and their life time (in hrs) is recorded in the form of a frequency table given below:
Life time (in hours) | 300 | 500 | 700 | 900 | 1100 |
Frequency | 10 | 12 | 23 | 25 | 10 |
One bulb is selected at random from the lot. The probability that its life is 1150 hours, is
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 (in Rs) |
Number of Television/household | |||
0 | 1 | 2 | Above 2 | |
< 10000 | 20 | 80 | 10 | 0 |
10000 – 14999 | 10 | 240 | 60 | 0 |
15000 – 19999 | 0 | 380 | 120 | 30 |
20000 – 24999 | 0 | 520 | 370 | 80 |
25000 and above | 0 | 1100 | 760 | 220 |
Find the probability:
- of a household earning Rs 10000 – Rs 14999 per year and having exactly one television.
- of a household earning Rs 25000 and more per year and owning 2 televisions.
- of a household not having any television.
A recent survey found that the ages of workers in a factory is distributed as follows:
Age (in years) | 20 – 29 | 30 – 39 | 40 – 49 | 50 – 59 | 60 and above |
Number of workers | 38 | 27 | 86 | 46 | 3 |
If a person is selected at random, find the probability that the person is:
- 40 years or more
- under 40 years
- having age from 30 to 39 years
- under 60 but over 39 years