Draw a histogram for the following data :

Classes	Frequency
59 - 65	10
66 - 72	5
73 - 79	25
80 - 86	15
87 - 93	30
94 - 100	10

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

Adjustment factor = (Lower limit of one class - Upper limit of previous class) / 2

= $\dfrac{66 - 65}{2} = \dfrac{1}{2}$

= 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 given data is :

Steps of construction of histogram :

1. Since, the scale on x-axis starts at 58.5, a break (kink) is shown near the origin on x-axis to indicate that the graph is drawn to scale beginning at 58.5

2. Take 2 cm along x-axis = 7 units.

3. Take 1 cm along y-axis = 5 units.

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

The required histogram is shown in the adjoining figure.