Question

In a study of diabetic patients in a village, the following observations were noted.
$\begin{array}{ccccccc}\text{Age in years}& 10-20& 20-30& 30-40& 40-50& 50-60& 60-70\\ \text{Number of patients}& 2& 5& 12& 19& 9& 4\end{array}$
Represent the above data by a frequency polygon.

Answer 1

Sol:

Age in years	10-20	20-30	30-40	40-50	50-60	60-70
No. of patients	2	5	12	19	9	4

In order to draw, frequency polygon, we require class marks. The class mark of a class interval is:

$\frac{upperlimit+lowerlimit}{2}$

The frequency distribution table with class marks is given below:

$\frac{upperlimit+lowerlimit}{2}$

The frequency distribution table with class marks is given below:

Class interval	Class marks	Frequency
0-10	5	0
10-20	15	2
20-30	25	5
30-40	35	12
40-50	45	19
50-60	55	9
60-70	65	4
70-80	75	0

In the above table, we have taken imaginary class intervals 0-10 at beginning and 70-80 at the end, each with frequency zero. Now take class marks along x-axis and the corresponding frequencies along y-axis.

Plot points (5, 0), (15, 2), (25, 5), (35, 12), (45, 19), (55, 9), (65, 4) and (75, 0) and draw line segments.