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Question
Construct a frequency polygon without using a histogram for the following frequency distribution :
| Class Mark | 10 | 15 | 20 | 25 | 30 | 35 | 40 |
| Frequency | 4 | 20 | 40 | 45 | 30 | 25 | 5 |
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Solution
Steps :
1. On the x-axis , take 1 cm as 5 units and plot class interval.
2. On the y-axis , take 1 cm as 5 units and plot frequency.
3. Mark the given data on the graph. (10,4),(15,20),(20,40),(25,45),(30,30),(35,25),(40,5)
4. Mark two more midpoints of zero frequency on x-axis at the start and at the end.
5. Now connect the points using staright lines.
| Class Mark | Frequency |
| 10 | 4 |
| 15 | 20 |
| 20 | 40 |
| 25 | 45 |
| 30 | 30 |
| 35 | 25 |
| 40 | 5 |
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RELATED QUESTIONS
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 |
For which of these would you use a histogram to show the data?
(a) The number of letters for different areas in a postman’s bag.
(b) The height of competitors in an athletics meet.
(c) The number of cassettes produced by 5 companies.
(d) The number of passengers boarding trains from 7:00 a.m. to 7:00 p.m. at a station.
Give reasons for each.
Draw histogram for the following frequency distributions:
| Class Interval | 30 – 39 | 40 – 49 | 50 – 59 | 60 – 69 | 70 – 79 |
| Frequency | 24 | 16 | 09 | 15 | 20 |
| Electricity bill (₹) | 0 - 200 | 200 - 400 | 400 - 600 | 600 - 800 | 800 - 1000 |
| Families | 240 | 300 | 450 | 350 | 160 |
Find the lower quartile, the upper quartile, the interquartile range and the semi-interquartile range for the following frequency distributions:
| Marks | 25 | 30 | 35 | 40 | 45 | 50 |
| No. of students | 6 | 15 | 12 | 10 | 18 | 9 |
Construct histograms for following frequency distribution:
| Class Mark | 6 | 12 | 18 | 24 | 30 | 36 |
| Frequency | 8 | 12 | 15 | 18 | 25 | 7 |
The marks scored by students in Mathematics in a certain examination are given below :
| Marks Scored | Number of Students |
| 0 - 20 | 6 |
| 20 - 40 | 9 |
| 40 - 60 | 14 |
| 60 - 80 | 16 |
| 80 - 100 | 5 |
Draw histogram for the above data.
Identify the following data can be represented in a histogram?
Production of cycles in different years
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.
