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प्रश्न
The following frequency distribution table shows marks obtained by 180 students in Mathematics examination.
| Marks | No. of students |
| 0 – 10 | 25 |
| 10 – 20 | x |
| 20 – 30 | 30 |
| 30 – 40 | 2x |
| 40 – 50 | 65 |
Find the value of x. Also draw a histogram representing the above information.
उत्तर
25 + x + 30 + 2x + 65 = 180
3x + 120 = 180
3x = 180 − 120
3x = 60
x = `60/3`
x = 20
| Marks | No. of students |
| 0 – 10 | 25 |
| 10 – 20 | 20 |
| 20 – 30 | 30 |
| 30 – 40 | 40 |
| 40 – 50 | 65 |
| Total | 180 |
संबंधित प्रश्न
Represent the following data by Histogram:
|
Price of Sugar per kg (in Rs.) |
Number of Weeks |
| 18-20 | 4 |
| 20-22 | 8 |
| 22-24 | 22 |
| 24-26 | 12 |
| 26-28 | 8 |
| 28-30 | 6 |
Draw histogram and frequency polygon on the same graph paper for the following frequency distribution
| Class | Frequency |
| 15-20 | 20 |
| 20-25 | 30 |
| 25-30 | 50 |
| 30-35 | 40 |
| 35-40 | 25 |
| 40-45 | 10 |
| Electricity bill (₹) | 0 - 200 | 200 - 400 | 400 - 600 | 600 - 800 | 800 - 1000 |
| Families | 240 | 300 | 450 | 350 | 160 |
The following histogram shows the frequency distribution f the ages of 22 teachers in a school:
(i) What is the number of eldest and youngest teachers in the school?
(ii) Which age group teachers are more in the school and which least?
(iii) What is the size of the classes?
(iv) What are the class marks of the classes?
The weekly wages (in Rs.) of 30 workers in a factory are given:
830, 835, 890, 810, 835, 836, 869, 845, 898, 890, 820, 860, 832, 833, 855, 845, 804, 808, 812, 840, 885, 835, 835, 836, 878, 840, 868, 890, 806, 840
Mark a frequency table with intervals as 800-810, 810-820 and so on, using tally marks. Also, draw a histogram and answer the following questions:
(i) Which group has the maximum number of workers?
(ii) How many workers earn Rs 850 and more?
(iii) How many workers earn less than Rs 850?
Construct histograms for following frequency distribution:
| Class Interval | 130-140 | 140-150 | 150-160 | 160-170 | 170-180 |
| Frequency | 24 | 16 | 29 | 20 | 11 |
Construct a frequency polygon without using a histogram for the following frequency distribution :
| Class Interval | 10-20 | 20-40 | 40-60 | 60-80 | 80-100 |
| Frequency | 9 | 17 | 15 | 20 | 14 |
The time taken, in seconds, to solve a problem for each of 25 persons is as follows:
| 16 | 20 | 26 | 27 | 28 |
| 30 | 33 | 37 | 38 | 40 |
| 42 | 43 | 46 | 46 | 47 |
| 48 | 49 | 50 | 53 | 58 |
| 59 | 60 | 64 | 52 | 20 |
(i) Construct a frequency distribution for these data using a class interval of 10 seconds.
(ii) In a school the weekly pocket money of 50 students is as follow's:
| Weekly pocket money (₹) | No. of student |
| 40 - 50 | 2 |
| 59 - 60 | 8 |
| 60 - 70 | 12 |
| 70 - 80 | 14 |
| 80 - 90 | 8 |
| 90 - 100 | 6 |
Draw a histogram and a frequency polygon on the same graph. Find mode from the graph.
Draw the histogram for the following frequency distribution and hence estimate the mode for the distribution.
| Class | Frequency |
| 0 - 5 | 2 |
| 5 - 10 | 7 |
| 10 - 15 | 18 |
| 15 - 20 | 10 |
| 20 - 25 | 8 |
| 25 - 30 | 5 |
| Total | 24 |
Draw a histogram to represent the following data:
| Pocket money in ₹ | No. of Students |
| 150 - 200 | 10 |
| 200 - 250 | 5 |
| 250 - 300 | 7 |
| 300 - 350 | 4 |
| 350 - 400 | 3 |
A graph that displays data that changes continuously over the periods of time is _________
The marks obtained by 50 students in Mathematics are given below.
(i) Make a frequency distribution table taking a class size of 10 marks
(ii) Draw a histogram and a frequency polygon.
| 52 | 33 | 56 | 52 | 44 | 59 | 47 | 61 | 49 | 61 |
| 47 | 52 | 67 | 39 | 89 | 57 | 64 | 58 | 63 | 65 |
| 32 | 64 | 50 | 54 | 42 | 48 | 22 | 37 | 59 | 63 |
| 36 | 35 | 48 | 48 | 55 | 62 | 74 | 43 | 41 | 51 |
| 08 | 71 | 30 | 18 | 43 | 28 | 20 | 40 | 58 | 49 |
Histogram is a graph of a ________ frequency distribution
Try yourself
- Next time when you watch your favourite TV programme, count the number of advertisements during each break. Use tally marks. Put a dot below the tally when you find children in any advertisement.
- Compare with your friends. Do you get different answers?
From the histogram given on the right, we can say that 1500 males above the age of 20 are literate.
Show the following data by a frequency polygon:
| Electricity bill (₹) | Families |
| 200 – 400 | 240 |
| 400 – 600 | 300 |
| 600 – 800 | 450 |
| 800 – 1000 | 350 |
| 1000 – 1200 | 160 |
The given graph with a histogram represents the number of plants of different heights grown in a school campus. Study the graph carefully and answer the following questions:
- Make a frequency table with respect to the class boundaries and their corresponding frequencies.
- State the modal class.
- Identify and note down the mode of the distribution.
- Find the number of plants whose height range is between 80 cm to 90 cm.
The table given below shows the runs scored by a cricket team during the overs of a match.
| Overs | Runs scored |
| 20 – 30 | 37 |
| 30 – 40 | 45 |
| 40 – 50 | 40 |
| 50 – 60 | 60 |
| 60 – 70 | 51 |
| 70 – 80 | 35 |
Use graph sheet for this question.
Take 2 cm = 10 overs along one axis and 2 cm = 10 runs along the other axis.
- Draw a histogram representing the above distribution.
- Estimate the modal runs scored.
