Question

Draw a histogram for the following data

Marks	10-15	15-20	20-25	25-30	30-40	40-60	60-80
Number of candidates	7	9	8	5	12	12	8

Answer 1

Here the classes are of unequal width, so we use the adjusted frequencies instead of frequency

The adjusted frequency of class = (Minimum class size/class size) x frequency of class

Here minimum class size is 5

The histogram is shown in the graph below.