The following table shows the number of illiterate persons in the age group (10 - 69) in a town

Age group (in years)	No. of illiterate persons
10 - 19	50
20 - 29	125
30 - 39	190
40 - 49	275
50 - 59	340
60 - 69	410

Draw a histogram to represent the above data.

The following frequency distribution is discontinuous, to convert it into continuous frequency distribution,

$\Rightarrow \text{Adjustment factor} = \dfrac{\text{Lower limit of one class - Upper limit of previous class}}{2} \\[1em] = \dfrac{20 - 19}{2} \\[1em] = \dfrac{1}{2} \\[1em] = 0.5$

Subtract the adjustment factor (0.5) from all the lower limits and add the adjustment factor (0.5) to all the upper limits.

Continuous frequency distribution for the given data is :

Steps of construction :

1. Take 2 cm along x-axis = 10 years

2. Take 1 cm along y-axis = 50 units

3. A kink is drawn near x-axis to show that the scale starts from 9.5 and not zero.

4. Construct rectangles corresponding to the above continuous frequency distribution table.

The required histogram is shown in the below figure: