What does the total area under a frequency curve represent?

Data represented through arithmetic line graph help in understanding:

Width of bars in a bar diagram need not be equal.

Width of rectangles in a histogram should essentially be equal.

 Histogram can only be formed with continuous classification of data.

Histogram and column diagram are the same method of presentaton of data.

Mode of a frequency distribution can be known graphically with the help of histogram.

Median of a frequency distribution cannot be known from the ogives.

What kind of diagrams are more effective in representing the following:

(i) Monthly rainfall in a year.

(ii) Composition of the population of Delhi by religion.

(iii) Components of cost in a factory.

Suppose you want to emphasise the increase in the share of urban non-workers and lower level of urbanisation in India as shown in Example 4.2. How would you do it in the tabular form?

How does the procedure of drawing a histogram differ when class intervals are unequal in comparison to equal class intervals in a frequency table?