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प्रश्न
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 |
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उत्तर
Steps :
1. Find class mark by calculating the average of the class interval.
2. On the x-axis , take 1 cm as 5 units and plot class interval.
3. On the y-axis , take 1 cm as 5 units and plot frequency.
4. plot the points on the graph. (15,9),(30,17),(50,15),(70,20),(90,14).
5. Mark two more midpoints of zero frequency on x-axis at the start and at the end .
6. Now connect the points using staright lines.
| Class Interval | Class mark | Frequency |
| 10-20 | `= (10+20)/2 = 15` | 9 |
| 20-40 | `= (20+40)/2 = 30` | 17 |
| 40-60 | `= (40+60)/2 = 50` | 15 |
| 60-80 | `= (60 + 80)/2 = 70` | 20 |
| 80-100 | `= (80 + 100)/2 = 90` | 14 |

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संबंधित प्रश्न
Draw the frequency polygon for the following frequency distribution
| Rainfall (in cm) | No. of Years |
| 20 — 25 | 2 |
| 25 — 30 | 5 |
| 30 — 35 | 8 |
| 35 — 40 | 12 |
| 40 — 45 | 10 |
| 45 — 50 | 7 |
Draw a histogram for the frequency table made for the data in Question 3 and answer the following questions.
(1) Which group has the maximum number of workers?
(2) How many workers earn Rs 850 and more?
(3) How many workers earn less than Rs 850?
Draw a histogram to represent the following data:
| Monthly salary (in Rs) | Number of teachers |
| 5600−5700 | 8 |
| 5700−5800 | 4 |
| 5800−5900 | 3 |
| 5900−6000 | 5 |
| 6000−6100 | 2 |
| 6100−6200 | 3 |
| 6200−6300 | 1 |
| 6300−6400 | 2 |
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?
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 _________
Draw a histogram for the following data.
| Class Interval | 0 − 10 | 10 − 20 | 20 − 30 | 30 − 40 | 40 − 50 | 50 − 60 |
| No. of students | 5 | 15 | 23 | 20 | 10 | 7 |
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 |
From the histogram given on the right, we can say that 1500 males above the age of 20 are literate.

