Draw a histogram and the frequency polygon from the following data:
Class interval20−2525−3030−3535−4040−4545−50Frequency3024522846100
Sol:
The given frequency distribution is as below:
Class intervals | 20-25 | 25-30 | 30-35 | 35-40 | 40-45 | 45-50 |
Frequency | 30 | 24 | 52 | 28 | 46 | 10 |
Take class intervals along x-axis and frequency along the y-axis and draw rectangles of width equal to the size of the class intervals and height equal to the corresponding frequencies. Thus we get required histogram.
Now take imaginary class intervals 15-20 at the beginning and 50-55 at the end, each with frequency zero and joins the midpoint of the top of the rectangle to get the required frequency polygon.