CA Foundation · Quantitative Aptitude · Statistical Description of Data
A histogram is drawn for a continuous frequency distribution with equal class widths. Which statement about the heights of its rectangles is correct?
With equal class widths, the height of each histogram rectangle is proportional to the class frequency. Area then also reflects frequency. Cumulative frequencies belong to ogives, and mid-values are plotted on the horizontal axis of a frequency polygon, so neither determines the rectangle heights.
- AEach height is proportional to the class frequencyCorrect
- BEach height is proportional to the class mid-value
- CEach height is proportional to the cumulative frequency
- DEach height is equal to the class width
Explanation
With equal class widths, the area of a rectangle is proportional to its height, so the height is proportional to the class frequency. Cumulative frequencies are plotted in an ogive, not in a histogram. Mid-values are used for a frequency polygon on the x-axis, not for heights.
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