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Frequency Table

Frequency is referred as repetition. In statistics, frequency of a particular variable or an observation is a number which indicates how many number of times the variable or observation is repeated in the given data.

When the data is scattered, one may not know exactly what is the frequency of a particular observation. In order to make it convenient, frequency tables were introduced. Frequency table is a table that represents frequencies of each element in front of it.
It is used to represent variables systematically that occur one or more times in a sample.

 Related Calculators Frequency Calculator Calculate Relative Frequency Frequency and Wavelength Calculator Frequency Distribution Calculator

Construction of Frequency Table

Case 1: Ungrouped Frequency Table
An ungrouped frequency table does not consist of class intervals. When data is variables present in a sample. Each observation is noted with its corresponding tally marks as shown in the following example.

Let us consider the following data:
2, 3, 3, 5, 7, 9, 7, 8, 9, 9, 2, 5, 3, 9, 3, 2, 5, 9, 8, 7, 3, 5, 7, 9, 8, 5, 2, 3
The frequency table for above data is: Case 2: Grouped Frequency Table
A grouped frequency table does have classes. The observations lying in each class interval are noted with corresponding tally marks and their frequency is written in front of each interval. Refer the following example .

Construct a grouped frequency table for the following data :
8, 10, 43, 15, 22, 34, 23, 45, 28, 49, 30, 21, 29, 17, 33, 39, 41, 48, 33, 25
Here,
Lowest observation = 8
Highest observation = 49
Difference = 49 - 8 = 41
If we take 10 as the width of class interval, then
Number of classes = $\frac{41}{10}$ = 4.1
Which means 5 classes are required.
Required frequency table is given below : More topics in  Frequency Table Frequency Distribution Cumulative Frequency
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