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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.
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संबंधित प्रश्न
Represent the following data by Histogram:
|
Price of Sugar per kg (in Rs.) |
Number of Weeks |
| 18-20 | 4 |
| 20-22 | 8 |
| 22-24 | 22 |
| 24-26 | 12 |
| 26-28 | 8 |
| 28-30 | 6 |
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.
Draw histogram for the following frequency distributions:
| Class Interval | 30 – 39 | 40 – 49 | 50 – 59 | 60 – 69 | 70 – 79 |
| Frequency | 24 | 16 | 09 | 15 | 20 |
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 table shows the investment made by some families. Show
the information by a histogran.
| Investment (Thousand Rupees) |
10-15 | 15-20 | 20-25 | 25-30 | 30-35 |
| No. of families | 30 | 50 | 60 | 55 | 15 |
Draw a histogram of the following data:
| Class interval: | 10−15 | 15−20 | 20−25 | 25−30 | 30−35 | 34−40 |
| Frequency: | 30 | 98 | 80 | 58 | 29 | 50 |
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 Mark | 15 | 25 | 35 | 45 | 50 | 55 | 60 |
| Frenuencv | 6 | 12 | 15 | 18 | 25 | 14 | 10 |
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 |
Following table present educational level (middle stage) of females in Arunachal pradesh according to 1981 census:
| Age group | Number of females (to the nearest ten) |
| 10 - 14 | 300 |
| 15 - 19 | 980 |
| 20 - 24 | 800 |
| 25 - 29 | 380 |
| 30 - 34 | 290 |
Draw a histogram to represent the above data.
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.
(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.
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 |
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?
Histogram shows the number of people owning the different number of books. Answer the question based on it.
The number of people having books more than 20 and less than 40 is ______.
The following pictorial representation of data is a histogram.
Prepare a histogram from the frequency distribution table obtained in question 93.
Use graph paper for this question. Estimate the mode of the given distribution by plotting a histogram. [Take 2 cm = 10 marks along one axis and 2 cm = 5 students along the other axis]
| Daily wages (in ₹) | 30 - 40 | 40 - 50 | 50 - 60 | 60 - 70 | 70 - 80 |
| No. of Workers | 6 | 12 | 20 | 15 | 9 |
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.
