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प्रश्न
Construct a frequency polygon for the following data:
| Class-Intervals | 10-14 | 15-19 | 20-24 | 25-29 | 30-34 |
| Frequency | 5 | 8 | 12 | 9 | 4 |
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उत्तर
The class intervals are inclusive. We will first convert them into the exclusive form.
| Class-Interval | Frequency |
| 9.5-14.5 | 5 |
| 14.5-19.5 | 8 |
| 19.5-24.5 | 12 |
| 24.5-29.5 | 9 |
| 29.5-34.5 | 4 |
Steps:
- Draw a histogram for the given data.
- Mark the mid-point at the top of each rectangle of the histogram drawn.
- Also, mark the mid-point of the immediately lower class-interval and the mid-point of the immediately higher class-interval.
- Join the consecutive mid-points marked by straight lines to obtain the required frequency polygon.
The required frequency polygon is as follows:

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संबंधित प्रश्न
Read the bar graph shown in Fig. 23.10 and answer the following questions
(i) What is the information given by the bar graph?

(ii) What was the number of commercial banks in 1977?
(iii) What is the ratio of the number of commercial banks in 1969 to that in 1980?
(iv) State whether true or false:
The number of commercial banks in 1983 is less than double the number of commercial banks in 1969.
The following table shows the number of Maruti cars sold by five dealers in a particular month:
| Dealer: | Saya | Bagga Links | D.D. Motors | Bhasin Motors | Competent |
| Cars sold: | 60 | 40 | 20 | 15 | 10 |
Represent the above information by a pictograph.
The expenditure (in 10 crores of rupees) on health by the Government of India during the various five year plans is shown below:
| Plans: | I | II | III | IV | V | VI |
| Expenditure on health (in 10 crores of rupees) |
7 | 14 | 23 | 34 | 76 | 182 |
Construct a bar graph to represent the above data.
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 |
In a frequency distribution, ogives are graphical representation of
A histogram is a pictorial representation of the grouped data in which class intervals and frequency are respectively taken along
Construct a combined histogram and frequency polygon for the following frequency distribution:
| Class-Intervals | 10 - 20 | 20 - 30 | 30 - 40 | 40 - 50 | 50 - 60 |
| Frequency | 3 | 5 | 6 | 4 | 2 |
Mr. Kapoor compares the prices (in Rs.) of different items at two different shops A and B. Examine the following table carefully and represent the data by a double bar graph.
| Items | Price (in ₹) at the shop A | Price (in ₹) at the shop B |
|
Tea-set |
900 | 950 |
|
Mixie |
700 | 800 |
|
Coffee-maker |
600 | 700 |
|
Dinner set |
600 | 500 |
The marks obtained (out of 100) by a class of 80 students are given below:
| Marks | Number of students |
| 10 – 20 | 6 |
| 20 – 30 | 17 |
| 30 – 50 | 15 |
| 50 – 70 | 16 |
| 70 – 100 | 26 |
Construct a histogram to represent the data above.
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 a histogram and frequency polygon representing the data above.
