Mathematics
Draw a frequency polygon for the following data :
| Class intervals | Frequency |
|---|---|
| 40 - 50 | 15 |
| 50 - 60 | 28 |
| 60 - 70 | 45 |
| 70 - 80 | 32 |
| 80 - 90 | 41 |
| 90 - 100 | 18 |
Answer
Frequency distribution table :
| Class intervals | Class marks | Frequency |
|---|---|---|
| 40 - 50 | 45 | 15 |
| 50 - 60 | 55 | 28 |
| 60 - 70 | 65 | 45 |
| 70 - 80 | 75 | 32 |
| 80 - 90 | 85 | 41 |
| 90 - 100 | 95 | 18 |
Steps to draw frequency polygon :
Since, the scale on x-axis starts at 30, a kink is shown near the origin on x-axis to indicate that the graph is drawn to scale beginning at 30.
Take 1 cm along x-axis = 10 units.
Take 1 cm along y-axis = 5 units.
Find the mid-points of class-intervals.
Find points corresponding to given frequencies of classes and the mid-points of class-intervals, and plot them.
Join consecutive points by line segments.
Join first end point with mid-point of class 30 - 40 with zero frequency and join the other end with mid-point of class 100 - 110 with zero frequency.
The required frequency polygon is shown below:
Related Questions
In a class of 60 students, the marks obtained in a monthly test were as under :
Marks Students 10 - 20 10 20 - 30 25 30 - 40 12 40 - 50 08 50 - 60 05 Draw a histogram for the following data :
Classes Frequency 59 - 65 10 66 - 72 5 73 - 79 25 80 - 86 15 87 - 93 30 94 - 100 10 In a class of 90 students, the marks obtained in a weekly test were as under :
Marks No. of students 16 - 20 4 21 - 25 12 26 - 30 18 31 - 35 26 36 - 40 14 41 - 45 10 46 - 50 6 Draw a frequency polygon for the above data.
Draw a histogram for the following frequency distribution :
Age (in years) No. of children below 2 12 below 4 15 below 6 36 below 8 45 below 10 72 below 12 90