Advertisements
Advertisements
प्रश्न
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 |
उत्तर
The total number of trials is 40.
Remember the empirical or experimental or observed frequency approach to probability.
If n be the total number of trials of an experiment and A is an event associated to it such that A happens in m-trials. Then the empirical probability of happening of event A is denoted by P (A) and is given by
P(A) = `m/n`
Let A1 be the event that the birth month of a chosen student is august.
The number of times A1 happens is 5.
Therefore, we have
` P(A_1)=5/40`
=`1/8`
APPEARS IN
संबंधित प्रश्न
1500 families with 2 children were selected randomly, and the following data were recorded:-
| Number of girls in a family | 2 | 1 | 0 |
| Number of families | 475 | 814 | 211 |
Compute the probability of a family, chosen at random, having
(i) 2 girls (ii) 1 girl (iii) No girl
Also check whether the sum of these probabilities is 1.
Given below is the frequency distribution of wages (in Rs) of 30 workers in a certain factory:
| Wages (in Rs) | 110-130 | 130-150 | 150-170 | 170-190 | 190-210 | 210-230 | 230-250 |
| No. of workers | 3 | 4 | 5 | 6 | 5 | 4 | 3 |
A worker is selected at random. Find the probability that his wages are:
(i) less than Rs 150
(ii) at least Rs 210
(iii) more than or equal to 150 but less than Rs 210.
Define an elementary event.
Mark the correct alternative in each of the following:
The probability of an impossible event is
The percentage of attendance of different classes in a year in a school is given below:
| Class: | X | IX | VIII | VII | VI | V |
| Attendance: | 30 | 62 | 85 | 92 | 76 | 55 |
What is the probability that the class attendance is more than 75%?
In a sample study of 642 people, it was found that 514 people have a high school certificate. If a person is selected at random, the probability that the person has a high school certificate is ______.
Two coins are tossed 1000 times and the outcomes are recorded as below:
| Number of heads | 2 | 1 | 0 |
| Frequency | 200 | 550 | 250 |
Based on this information, the probability for at most one head is
Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the following table:
| Number of defective bulbs | 0 | 1 | 2 | 3 | 4 | 5 | 6 | more than 6 |
| Frequency | 400 | 180 | 48 | 41 | 18 | 8 | 3 | 2 |
One carton was selected at random. What is the probability that it has
- no defective bulb?
- defective bulbs from 2 to 6?
- defective bulbs less than 4?
Bulbs are packed in cartons each containing 40 bulbs. Seven hundred cartons were examined for defective bulbs and the results are given in the following table:
| Number of defective bulbs | 0 | 1 | 2 | 3 | 4 | 5 | 6 | more than 6 |
| Frequency | 400 | 180 | 48 | 41 | 18 | 8 | 3 | 2 |
One carton was selected at random. What is the probability that it has defective bulbs less than 4?
Over the past 200 working days, the number of defective parts produced by a machine is given in the following table:
| Number of defective parts |
0 | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 | 11 | 12 | 13 |
| Days | 50 | 32 | 22 | 18 | 12 | 12 | 10 | 10 | 10 | 8 | 6 | 6 | 2 | 2 |
Determine the probability that tomorrow’s output will have not more than 5 defective parts
