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Question
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.
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Solution
CI. Frequency 30 – 40 4 40 – 50 2 50 – 60 8 60 – 70 12 70 – 80 6 80 – 90 3 90 – 100 4 - Here, modal class is 60 – 70, with highest frequency of 12.
- From the given graph the mode of the distribution is 64.
- The number of plants whose height range is between 80 cm to 90 cm is 3.
RELATED QUESTIONS
The marks scored by students in Mathematics in a certain Examination are given below:
| Marks Scored | Number of Students |
| 0 — 20 | 3 |
| 20 — 40 | 8 |
| 40 — 60 | 19 |
| 60 — 80 | 18 |
| 80 — 100 | 6 |
Draw histogram for the above data.
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 |
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?
The following histogram shows the monthly wages (in Rs) of workers in a factory:
(i) In which wage-group the largest number of workers are being kept? What is their number?
(ii) What wages are the least number of workers getting? What is the number of such workers?
(iii) What is the total number of workers?
(iv) What is the factory size?
The weekly wages (in Rs.) of 30 workers in a factory are given:
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
Mark a frequency table with intervals as 800-810, 810-820 and so on, using tally marks. Also, draw a histogram and answer the following questions:
(i) Which group has the maximum number of workers?
(ii) How many workers earn Rs 850 and more?
(iii) How many workers earn less than Rs 850?
The following frequency distribution table shows marks obtained by 180 students in Mathematics examination.
| Marks | No. of students |
| 0 - 10 | 25 |
| 10 - 20 | x |
| 20 - 30 | 30 |
| 30 - 40 | 2x |
| 40 - 50 | 65 |
Find the value of x. Also draw a histogram representing the above information.
The total area of the histogram is _________ to the total frequency of the given data
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?
The marks obtained by 50 students in Mathematics are given below.
(i) Make a frequency distribution table taking a class size of 10 marks
(ii) Draw a histogram and a frequency polygon.
| 52 | 33 | 56 | 52 | 44 | 59 | 47 | 61 | 49 | 61 |
| 47 | 52 | 67 | 39 | 89 | 57 | 64 | 58 | 63 | 65 |
| 32 | 64 | 50 | 54 | 42 | 48 | 22 | 37 | 59 | 63 |
| 36 | 35 | 48 | 48 | 55 | 62 | 74 | 43 | 41 | 51 |
| 08 | 71 | 30 | 18 | 43 | 28 | 20 | 40 | 58 | 49 |
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 |
