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After reading this article you will learn about the computation of frequency distribution.
Any numerical data obtained from quantitative parameters has to be arrange in order systematically and put under a particular system of analysis to obtain a meaningful conclusion.
A data obtained from 50 Nigella sativa plants regarding number of capsules per plant are as follows:
First, the data has to be arrange in order of magnitude:
The data is a ungrouped one and can be represented in tabular form for Observing mean capsule number per plant in more precise manner. However, this data can also be used to find out mean number of capsules/plant.
ɳ = 50, each data represent xi variables.
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Therefore,
Mean (x̅) = Ʃ xi/ɳ =1402/50 = 28.04.
Tabulated form of the data with their frequency of occurrence.
The number of plants observed under each xi variable (category) is frequency of the class concerned.
The same ungroup data can be grouped having regular class interval.
In the present problem frequency in each class is low and hence there is little difficulty in finding out fx. However, if the frequency in each class is too high in such case mean can be found out using assumed mean. Assumed mean is taken from the xi-values itself (class value), any value may be consider but middle values are generally taken for convenience.
Class interval can only be used when it is regular.
