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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 |
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 |
APPEARS IN
संबंधित प्रश्न
The histogram below represents the scores obtained by 25 students in a mathematics mental test. Use the data to:
- Frame a frequency distribution table.
- To calculate mean.
- To determine the Modal class.
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|
Investment
(Thousand Rupees) |
10 - 15 | 15 - 20 | 20 - 25 | 25 - 30 | 30 - 35 |
| No. of families | 30 | 50 | 60 | 55 | 15 |
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 |
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| Class Interval | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Frequency | 8 | 20 | 34 | 22 | 10 | 6 |
Represent the following data by histogram:
| Price of sugar Per kg (in Rs) | Number of weeks |
| 28-30 | 4 |
| 30-32 | 8 |
| 32-34 | 22 |
| 34-36 | 12 |
| 36-38 | 6 |
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.
Draw a histogram and frequency polygon to represent the following data (on the same scale) which shows the monthly cost of living index of a city in a period of 2 years:
| Cost of living Index | Number of months |
| 440 - 460 | 2 |
| 460 - 480 | 4 |
| 480 - 500 | 3 |
| 500 - 520 | 5 |
| 520 - 540 | 3 |
| 540 - 560 | 2 |
| 560 - 580 | 1 |
| 580 - 600 | 4 |
| 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 |
(Use a graph paper for this question.) The daily pocket expenses of 200 students in a school are given below:
| Pocket expenses (in ₹) |
Number of students (frequency) |
| 0 - 5 | 10 |
| 5 - 10 | 14 |
| 10 - 15 | 28 |
| 15 - 20 | 42 |
| 20 - 25 | 50 |
| 25 - 30 | 30 |
| 30 - 35 | 14 |
| 35 - 40 | 12 |
Draw a histogram representing the above distribution and estimate the mode from the graph.
Identify the following data can be represented in a histogram?
The number of votes polled from 7 am to 6 pm in an election
The total area of the histogram is _________ to the total frequency of the given data
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 |
Draw a histogram and the frequency polygon in the same diagram to represent the following data
| Weight (in kg) | 50 − 55 | 56 − 61 | 62 − 67 | 68 − 73 | 74 − 79 | 80 − 85 | 86 − 91 |
| No. of persons | 15 | 8 | 12 | 17 | 9 | 10 | 6 |
Draw a histogram for the following data.
| Mid Value (x) | 15 | 25 | 35 | 45 | 55 | 65 | 75 |
| Frequency (f) | 12 | 24 | 30 | 18 | 26 | 10 | 8 |
Try yourself
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| 10 – 20 | 5 |
| 20 – 30 | 5 |
| 30 – 40 | 10 |
| 40 – 50 | 8 |
| 50 – 60 | 0 |
| 60 – 70 | 2 |
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- Make a frequency table with respect to the class boundaries and their corresponding frequencies.
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- Identify and note down the mode of the distribution.
- Find the number of plants whose height range is between 80 cm to 90 cm.
