Question

explain how to contructed a grouped frequency distribution table

Answer 1

Grouped frequency distribution table is used to display a large set of data in a simple way. The process to create a group frequency table is as below

1. At first the total number of classes to be made is needed. Also we should count the total number of observation we had.

2. Then the class width is to calculate by dividing the range of the data by the number of classes.

3. Now find the least number and start making classes from that number and the class width should be the number which we have already found out.

4.the starting point and ending point of each classes are said to be the lower limit and upper limit of each class. We take an average of class limits of each classes. Then that average is subtracted from the lower limit of each cls and added to the upper limit of each classes. Then we rewrite the classes again and name that column class boundary. Usually we take lower limit - 0.5 and upper limit +0.5

5. Next we will calculate number of values fall in between each class boundary. Any points which will be the upper limit of any classes should be consider in the next class where that point will be the lower limit. This column is frequency.

6. Next column is relative frequency. It is calculated by dividing frequency of each columns by the total frequency.

7. The last column should be cumulative frequency. It is of two types. The first one is less than type which is calculated by adding the frequency of upto ith class for finding the frequency of that cls. Another one is more than type where we subtract the sums of frequency upto ith cls from the total frequency. But in most of the cases generally we use less than type cumulative frequency.

A frequency table should be of following form which is just a small demo.

Frequency table

Class limit	class boundary	frequency	relative frequency	cumulative frequency
45-50	44.5-50.5	2	0.4	2
51-56	50.5-56.5	3	0.5	5