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प्रश्न
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 |
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उत्तर
Steps :
1. Make the class intervals continuous by subtracting 0.5 from the lower limit of each class and add 0.5 to the upper limit of each class .
2. Find class mark by calculating the average of the class interval.
3. On the x-axis , take 1 cm as 5 units and plot class interval.
4. On the y-axis , take 1 cm as 5 units and plot frequency.
5. Plot the points on the graph. (5.5,8),(15.5,12),(25.5,10),(35.5,16),(45.5,6).
6. Mark two more midpoints of zero frequency on x-axis at the start and at the end.
7. Now connect the points using straight lines.
| Class Interval | Class Mark | Frequency |
| 0.5-10.5 | = `(0.5+10.5)/2 = 5.5` | 8 |
| 10.5-20.5 | = `(10.5+20.5)/2 = 15.5` | 12 |
| 20.5-30.5 | = `(20.5 + 30.5)/2 = 25.5` | 10 |
| 30.5-40.5 | = `(30.5 + 40.5)/2 = 35.5` | 16 |
| 40.5-50.5 | = `(40.5 + 50.5)/2 = 45.5` | 6 |
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संबंधित प्रश्न
Draw a histogram for the frequency table made for the data in Question 3 and answer the following questions.
(1) Which group has the maximum number of workers?
(2) How many workers earn Rs 850 and more?
(3) How many workers earn less than Rs 850?
Draw histogram and frequency polygon on the same graph paper for the following frequency distribution
| Class | Frequency |
| 15-20 | 20 |
| 20-25 | 30 |
| 25-30 | 50 |
| 30-35 | 40 |
| 35-40 | 25 |
| 40-45 | 10 |
The following table is based on the marks of the first term examination of 10th class students. Show the information by a histogram. Also, draw a frequency polygon with the help of the histogram.
| Class-mark of marks | 325 | 375 | 425 | 475 | 525 | 575 |
| No. of students | 25 | 35 | 45 | 40 | 32 | 20 |
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).
The following histogram shows the number of literate females in the age group of 10 to 40 years in a town:
(i) Write the age group in which the number of literate female is the highest.
(ii) What is the class width?
(iii) What is the lowest frequency?
(iv) What are the class marks of the classes?
(v) In which age group literate females are the least?
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 |
Represent the following data by histogram:
| Price of sugar Per kg (in Rs) | Number of weeks |
| 28-30 | 4 |
| 30-32 | 8 |
| 32-34 | 22 |
| 34-36 | 12 |
| 36-38 | 6 |
The marks scored by students in Mathematics in a certain examination are given below :
| Marks Scored | Number of Students |
| 0 - 20 | 6 |
| 20 - 40 | 9 |
| 40 - 60 | 14 |
| 60 - 80 | 16 |
| 80 - 100 | 5 |
Draw histogram for the above data.
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 frequency distribution in question 91.
