A random survey o

Here the class intervals are of different lengths.
So we have to calculate the adjusted frequency.

The required size of interval = minimum size of the interval
                                   = 2 - 1
                                   = 1

So the adjusted frequency is:

The class interval with minimum class size 1 is selected and the length of the rectangle is proportional to it.Taking the age of the children on x-axis and proportion of children per 1 year interval on the y-axis, the following histogram can be drawn: