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प्रश्न
The frequency distribution has been represented graphically as follows:
| Marks | 0 – 20 | 20 – 40 | 40 – 60 | 60 – 100 |
| Number of Students | 10 | 15 | 20 | 25 |

Do you think this representation is correct? Why?
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उत्तर
No, here the widths of the rectangles are varying, so we need to make certain modifications in the length of the rectangles so that the areas are proportional to the frequencies.
We proceed as follows:
1. Select a class interval with the minimum class size, here the minimum class size is 20.
2. The length of the rectangles are then modified to be proportionate to the class size 20.
Now, we get the following modified table:
| Marks | Number of students (Frequency) |
Width of the class |
Length of the rectangle |
| 0 – 20 | 10 | 20 | `10/20 xx 20 = 10` |
| 20 – 40 | 15 | 20 | `15/20 xx 20 = 15` |
| 40 – 60 | 20 | 20 | `20/20 xx 20 = 20` |
| 60 – 100 | 25 | 40 | `25/40 xx 20 = 12.5` |
So, the correct histogram with varying width is given below:
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संबंधित प्रश्न
Given below are the seats won by different political parties in the polling outcome of a state assembly elections:-
| Political Party | A | B | C | D | E | F |
| Seats Won | 75 | 55 | 37 | 29 | 10 | 37 |
- Draw a bar graph to represent the polling results.
- Which political party won the maximum number of seats?
Read the following bar graph and answer the following questions:

(i) What information is given by the bar graph?
(ii) Which state is the largest producer of rice?
(iii) Which state is the largest producer of wheat?
(iv) Which state has total production of rice and wheat as its maximum?
(v) Which state has the total production of wheat and rice minimum?
The distribution of heights (in cm) of 96 children is given below. Construct a histogram and a frequency polygon on the same axes.
| Height (in cm): | 124 to 128 |
128 to 132 |
132 to 136 |
136 to 140 |
140 to 144 |
144 to 148 |
148 to 152 |
152 to 156 |
156 to 160 |
160 to 164 |
| No. of Children: | 5 | 8 | 17 | 24 | 16 | 12 | 6 | 4 | 3 | 1 |
Draw frequency polygons for each of the following frequency distribution:
(a) using histogram
(b) without using histogram
|
C.I |
5 -15 | 15 -25 | 25 -35 | 35 - 45 | 45-55 | 55-65 |
| ƒ | 8 | 16 | 18 | 14 | 8 | 2 |
A hundred students from a certain locality use different modes of travelling to school as given below. Draw a bar graph.
| Bus | Car | Rickshaw | Bicycle | Walk |
| 32 | 16 | 24 | 20 | 8 |
For the following data, draw a pie graph.
| Subject | Hindi | English | Maths | Science | Social Study |
| Marks as percent | 60 | 45 | 42 | 48 | 75 |
Mr. Mirza’s monthly income is Rs. 7,200. He spends Rs. 1,800 on rent, Rs. 2,700 on food, Rs. 900 on the education of his children; Rs. 1,200 on Other things and saves the rest.
Draw a pie-chart to represent it.
In the following figure, there is a histogram depicting daily wages of workers in a factory. Construct the frequency distribution table.

Draw a histogram to represent the following grouped frequency distribution:
| Ages (in years) | Number of teachers |
| 20 – 24 | 10 |
| 25 – 29 | 28 |
| 30 – 34 | 32 |
| 35 – 39 | 48 |
| 40 – 44 | 50 |
| 45 – 49 | 35 |
| 50 – 54 | 12 |
Following table shows a frequency distribution for the speed of cars passing through at a particular spot on a high way:
| Class interval (km/h) | Frequency |
| 30 – 40 | 3 |
| 40 – 50 | 6 |
| 50 – 60 | 25 |
| 60 – 70 | 65 |
| 70 – 80 | 50 |
| 80 – 90 | 28 |
| 90 – 100 | 14 |
Draw the frequency polygon representing the above data without drawing the histogram.
