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Question
The weekly wages (in Rs) of 30 workers in a factory are.
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
Using tally marks make a frequency table with intervals as 800 − 810, 810 − 820 and so on.
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Solution
A frequency distribution table by using tally marks for the above data is as follows.
| Interval | Tally marks | Frequency |
| 800 − 810 |  |
3 |
| 810 − 820 |  |
2 |
| 820 − 830 |  |
1 |
| 830 − 840 |  |
9 |
| 840 − 850 |  |
5 |
| 850 − 860 |  |
1 |
| 860 − 870 |  |
3 |
| 870 − 880 |  |
1 |
| 880 − 890 | |
1 |
| 890 − 900 |  |
4 |
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RELATED QUESTIONS
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.
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.
A Mathematics aptitude test of 50 students was recorded as follows:
| Marks | 50 - 60 | 60 - 70 | 70 - 80 | 80 - 90 | 90 – 100 |
| No. of Students | 4 | 8 | 14 | 19 | 5 |
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Time alloted for the preparation of an examination by some students is shown in the table. Draw a histogram to show the information.
| Time (minutes) | 60 - 80 | 80 - 100 | 100 - 120 | 120 - 140 | 140 - 160 |
| No. of students | 14 | 20 | 24 | 22 | 16 |
The following table shows the investment made by some families. Show
the information by a histogran.
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10-15 | 15-20 | 20-25 | 25-30 | 30-35 |
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Given below is the frequency distribution of the heights of 50 students of a class:
| Class interval: | 140−145 | 145−150 | 150−155 | 155−160 | 160−165 |
| Frequency: | 8 | 12 | 18 | 10 | 5 |
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Find the lower quartile, the upper quartile, the interquartile range and the semi-interquartile range for the following frequency distributions:
| Variate | 10 | 11 | 12 | 13 | 14 | 15 | 16 | 17 | 18 | 19 | 20 |
| Frequency | 1 | 2 | 3 | 1 | 2 | 4 | 2 | 1 | 1 | 2 | 1 |
Construct histograms for following frequency distribution:
| Class Interval | 130-140 | 140-150 | 150-160 | 160-170 | 170-180 |
| Frequency | 24 | 16 | 29 | 20 | 11 |
Draw a histogram for the following frequency distribution.
|
Use of electricity (Unit)
|
50 - 70 | 70 - 90 | 90 - 110 | 110 - 130 | 130 - 150 | 150 - 170 |
| No. of families | 150 | 400 | 460 | 540 | 600 | 350 |
Distribution of height in cm of 100 people is given below:
| Class interval (cm) | Frequency |
| 145 - 155 | 3 |
| 155 - 165 | 35 |
| 165 - 175 | 25 |
| 175 - 185 | 15 |
| 185 - 195 | 20 |
| 195 - 205 | 2 |
Draw a histogram to represent 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 the histogram for the following frequency distribution and hence estimate the mode for the distribution.
| Class | Frequency |
| 0 - 5 | 2 |
| 5 - 10 | 7 |
| 10 - 15 | 18 |
| 15 - 20 | 10 |
| 20 - 25 | 8 |
| 25 - 30 | 5 |
| 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 |
The graphical representation of ungrouped data is ________
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 |
Form a continuous frequency distribution table and draw histogram from the following data.
| Age (in years) | No. of persons |
| Under 5 | 1 |
| Under 10 | 12 |
| Under 15 | 19 |
| Under 20 | 26 |
| Under 25 | 27 |
| Under 30 | 35 |
| Under 35 | 38 |
| Under 40 | 45 |
| Under 45 | 48 |
| Under 50 | 53 |
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
- Next time when you watch your favourite TV programme, count the number of advertisements during each break. Use tally marks. Put a dot below the tally when you find children in any advertisement.
- Compare with your friends. Do you get different answers?
In a histogram ______ are drawn with width equal to a class interval without leaving any gap in between.
From the histogram given on the right, we can say that 1500 males above the age of 20 are literate.
