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Results on Diagrams
☼ Results on Diagrams :
■ Histogram ( or column graph ) : For frequency distribution for grouped data, classes are converted into real class intervals, that is, class intervals whose endpoints are their class represented on the X – axis and their corresponding frequencies on the Y – axis by choosing proper scales. And hence we can get the Histogram ( or column graph ) of joined rectangles.
■ Frequency Polygon : When a grouped frequency distribution with equal class intervals is being given, we represent the mid–point on x-axis and the frequencies on y-axis. We complete the diagram in the form of a polygon by taking two more classes one at the beginning and the other at the end, each with frequency 0.
■ Frequency Polygon From Histogram : By joining the mid points of tops of rectangles of histogram, we obtain the frequency polygon.
■ Ogive ( Cumulative Frequency Curve ) : We mark the upper class limits along x-axis and cumulative frequencies along y-axis. Plot these points and join them to get a curve, called an ogive.
