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எங்கள் ஆசிரியர்களுடன் 1-ஆன்-1 ஆலோசனை நேரத்தைப் பெறுங்கள். டாப்பர் ஆவதற்கு நாங்கள் பயிற்சி அளிப்போம்

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Class interval and Class size:
Class interval or classes is the difference between the upper limit and the lower limit. The upper limit is the class's highest value, and the lower limit is the class's lowest value.
The difference between the successive upper limits or the successive lower limits is called as the class size or the class width.
Example:
Let us construct a frequency distribution table for the following 26 data using tally marks.
 
31, 32, 52, 60, 37, 49, 42, 56, 43, 55, 72, 84, 67, 75, 44, 41, 59, 57, 91, 98, 78, 66, 81, 88, 86, 58
 
Sol:
 
We can see that the data is very large, and the reader find it difficult to understand it. Hence, let us group the given data.
 
The minimum value is 31, and the maximum value is 91. We shall group the data as 30 - 39, 40 - 49, ..., 90 - 99, which are called as class intervals.
 
Consider the classes 30 - 39 and 40 - 49 to find the class size.
 
Consider the successive upper limits, then the class size = 40 - 30 = 10
 
Now, we shall tabulate the data.
 
Class intervalTally marksFrequency
30 - 39Figure 12.svg3
40 - 49Figure 14.svg5
50 - 59Figure 14.svg Figure 10.svg6
60 - 69Figure 12.svg3
70 - 79Figure 12.svg3
80 - 89Figure 13.svg4
90 - 99Figure 11.svg2
 
This table is called a frequency distribution table using grouped data.