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

Represent the above data by a frequency polygon.

$\begin{array}{ccccccc}\text{Age in years}& 10-20& 20-30& 30-40& 40-50& 50-60& 60-70\\ \text{Number of patients}& 2& 5& 12& 19& 9& 4\end{array}$

In order to draw, frequency polygon, we require class marks.
The class mark of a class interval is : $\frac{\text{lower limit + upper limit}}{2}$

The frequency distribution table with class marks is given below:

$\begin{array}{ccc}\text{Class - intervals}& \text{Class marks}& \text{Frequency}\\ 0-10& 5& 0\\ 10-20& 15& 2\\ 20-30& 25& 5\\ 30-40& 35& 12\\ 40-50& 45& 19\\ 50-60& 55& 9\\ 60-70& 65& 4\\ 70-80& 75& 0\end{array}$

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 frequency 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