Question

The ages (in years) of 360 patients treated in a hospital on a particular dayare given below.

$\begin{array}{ccccccc}\text{Age in years}& 10-20& 20-30& 30-40& 40-50& 50-60& 60-70\\ \text{Number of}& & & & & & \\ \text{patients}& 90& 40& 60& 20& 120& 30\end{array}$

Draw a histogram and a frequency polygon on the same graph to represent the above data.

Answer 1

The given frequency distribution is as under

$\begin{array}{ccccccc}\text{Age in years}& 10-20& 20-30& 30-40& 40-50& 50-60& 60-70\\ \text{Number of}& & & & & & \\ \text{patients}& 90& 40& 60& 20& 120& 30\end{array}$

Take class intervals i.e age in years along x-axis and number of patients of width equal to the size of the class intervals and height equal to the corresponding frequencies.

Thus we get the required histogram.

In order to draw frequency polygon,we take imaginary intervals 0-10 at the beginning and 70-80 at the end each with frequency zero and join the mid-points of top of the rectangles.

Thus, we obtain a complete frequency polygon, shown below: