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प्रश्न
The following histogram shows the frequency distribution f the ages of 22 teachers in a school:
(i) What is the number of eldest and youngest teachers in the school?
(ii) Which age group teachers are more in the school and which least?
(iii) What is the size of the classes?
(iv) What are the class marks of the classes?
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उत्तर
(i) The eldest (50-55 years) = 1 person
This is because the height of the rectangle with class interval 50-55 as base is 1 unit.
The youngest (20-25 years)= 2 persons
This is because the height of the rectangle with class interval 20-25 as base is 2 units.
(ii) The group containing the most number of teachers is 35-40 years. This is because the height of the rectangle with class interval 35-40 as base is the maximum.
The group containing the least number of teachers is 50-55 years. This is because the height of the rectangle with class interval 50-55 as base is the minimum.
(iii) Class size = The range between the upper and the lower boundaries of the class
For example, the size of the class 20-25 years is 5.
\[\text{ Class mark }= \frac{\text{ Upper limit }+\text{ Lower limit}{2}\]
For class 20 - 25:
\[\text{ Class mark }= \frac{20 + 25}{2} = \frac{45}{2} = 22 . 5\]
Similarly, the class marks of the other classes are 27.5; 32.5; 37.5; 42.5; 47.5; 52.5.
संबंधित प्रश्न
Draw the frequency polygon for the following frequency distribution
| Rainfall (in cm) | No. of Years |
| 20 — 25 | 2 |
| 25 — 30 | 5 |
| 30 — 35 | 8 |
| 35 — 40 | 12 |
| 40 — 45 | 10 |
| 45 — 50 | 7 |
Given below is the frequency distribution of driving speeds (in km/hour) of the vehicles of 400 college students:
| Speed (in km/hr) | No. of Students |
| 20-30 | 6 |
| 30-40 | 80 |
| 40-50 | 156 |
| 50-60 | 98 |
60-70 |
60 |
Draw Histogram and hence the frequency polygon for the above data.
The following is the frequency distribution of waiting time at ATM centre; draw histogram to represent the data:
| Waiting time (in seconds) |
Number of Customers |
| 0 -30 | 15 |
| 30 - 60 | 23 |
| 60 - 90 | 64 |
| 90 - 120 | 50 |
| 120 - 150 | 5 |
In the following table, the investment made by 210 families is shown. Present it in the form of a histogram.
|
Investment
(Thousand Rupees) |
10 - 15 | 15 - 20 | 20 - 25 | 25 - 30 | 30 - 35 |
| No. of families | 30 | 50 | 60 | 55 | 15 |
Observe the following frequency polygon and write the answers of the questions below it.
- Which class has the maximum number of students?
- Write the classes having zero frequency.
- What is the class-mark of the class, having frequency of 50 students?
- Write the lower and upper class limits of the class whose class mark is 85.
- How many students are in the class 80-90?
Draw a histogram to represent the following data:
| Monthly salary (in Rs) | Number of teachers |
| 5600−5700 | 8 |
| 5700−5800 | 4 |
| 5800−5900 | 3 |
| 5900−6000 | 5 |
| 6000−6100 | 2 |
| 6100−6200 | 3 |
| 6200−6300 | 1 |
| 6300−6400 | 2 |
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 a frequency polygon without using a histogram for the following frequency distribution :
| Class Interval | 1-10 | 11-20 | 21-30 | 31-40 | 41-50 |
| Frequency | 8 | 12 | 10 | 16 | 6 |
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 |
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 |
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 |
The total area of the histogram is _________ to the total frequency of the given data
Histogram is a graphical representation of ___________ data
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 |
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The number of people owning books less than 40 is ______.
Prepare a histogram from the frequency distribution table obtained in question 93.
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- Write the classes assuming all the classes are of equal width.
- What is the classes width?
- In which age group are literate females the least?
- In which age group is the number of literate females the highest?
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.
