Statistics — Important Questions

Used for continuous class intervals, Areas of rectangles are proportional to frequencies, Width of bars plays a significant role

A histogram is used for continuous class intervals, has no gaps between rectangles, and the areas of rectangles are proportional to frequencies. Unlike bar graphs, the width of bars is significant in histogram construction.

They are formed by joining midpoints of histogram bars, They are useful for comparing two datasets, They are used when data is continuous and very large, They always have the same area as the corresponding histogram

Frequency polygons are created by joining midpoints of histogram rectangles, are useful for comparing datasets, work with continuous large data, and maintain the same area as the histogram when properly constructed.

Class intervals with zero frequency

To complete a frequency polygon, we assume class intervals with zero frequency before the first class and after the last class. This helps make the area of the polygon equal to the area of the histogram.

Length of rectangles

When all class intervals have equal width in a histogram, the lengths (heights) of rectangles are proportional to frequencies. This is because area = length × width, and with constant width, length determines the area.