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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?
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.
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संबंधित प्रश्न
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 |
Draw a histogram from the above data using a graph paper and locate the mode.
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?
In a hypothetical sample of 20 people the amounts of money with them were found to be as follows:
114, 108, 100, 98, 101, 109, 117, 119, 126, 131, 136, 143, 156, 169, 182, 195, 207, 219, 235, 118.
Draw the histogram of the frequency distribution (taking one of the class intervals as 50 − 100).
Construct a histogram for the following data:
| Monthly school fee (in Rs): | 30−60 | 60−90 | 90−120 | 120−150 | 150−180 | 180−210 | 210−240 |
| Number of schools: | 5 | 12 | 14 | 18 | 10 | 9 | 4 |
Construct histograms for following frequency distribution:
| Class Interval | 0-10 | 10-20 | 20-30 | 30-40 | 40-50 | 50-60 |
| Frequency | 8 | 20 | 34 | 22 | 10 | 6 |
Construct histograms for following frequency distribution:
| Class Interval | 110-119 | 120-129 | 130-139 | 140-149 | 150-159 |
| Frequency | 15 | 23 | 30 | 20 | 16 |
The time taken, in seconds, to solve a problem for each of 25 persons is as follows:
| 16 | 20 | 26 | 27 | 28 |
| 30 | 33 | 37 | 38 | 40 |
| 42 | 43 | 46 | 46 | 47 |
| 48 | 49 | 50 | 53 | 58 |
| 59 | 60 | 64 | 52 | 20 |
(i) Construct a frequency distribution for these data using a class interval of 10 seconds.
(ii) In a school the weekly pocket money of 50 students is as follow's:
| Weekly pocket money (₹) | No. of student |
| 40 - 50 | 2 |
| 59 - 60 | 8 |
| 60 - 70 | 12 |
| 70 - 80 | 14 |
| 80 - 90 | 8 |
| 90 - 100 | 6 |
Draw a histogram and a frequency polygon on the same graph. Find mode from the graph.
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 |
In a village, there are 570 people who have cell phones. An NGO survey their cell phone usage. Based on this survey a histogram is drawn
How many of them use the cell phone for more than 5 hours?
In a village, there are 570 people who have cell phones. An NGO survey their cell phone usage. Based on this survey a histogram is drawn
Are people using cell phone for less than 1 hour?
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 |
Represent the following data by histogram:
| Price of Sugar (per kg in ₹) | Number of Weeks |
| 18 – 20 | 4 |
| 20 – 22 | 8 |
| 22 – 24 | 22 |
| 24 – 26 | 12 |
| 26 – 28 | 6 |
| 28 – 30 | 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?
The number of people having books more than 20 and less than 40 is ______.
Look at the histogram below and answer the questions that follow.
- How many students have height more than or equal to 135 cm but less than 150 cm?
- Which class interval has the least number of students?
- What is the class size?
- How many students have height less than 140 cm?
Prepare a histogram from the frequency distribution table obtained in question 93.
The following histogram shows the frequency distribution of teaching experiences of 30 teachers in various schools:
- What is the class width?
- How many teachers are having the maximum teaching experience and how many have the least teaching experience?
- How many teachers have teaching experience of 10 to 20 years?
The following table shows the classification of percentage of marks of students and the number of students. Draw frequency polygon from the table without drawing histogram:
| Result (Percentage) | Number of Students |
| 20 - 40 | 25 |
| 40 - 60 | 65 |
| 60 - 80 | 80 |
| 80 - 100 | 15 |
