Discrete and Continuous distributions:

A discrete distribution is one in which the data can only take on certain values, for example integers. 

Thus, in a discrete frequency distribution, the values of the variable are determined individually. The number of times each value occurs denotes the frequencies of the particular value or observation.

A continuous frequency distribution is a series in which the data are classified into different class intervals without gaps and their respective frequencies are assigned as per the class intervals and class width.

Continuous data is data that can take any value. Height, weight, temperature and length are all examples of continuous data.

Question: Calculate the variance and standard deviation of the following continuous frequency distribution

Solution:

 

Example: Prepare a discrete frequency distribution table for the following data.

12, 21, 21, 3, 9, 3, 6, 12, 13, 21, 15, 22, 3, 6, 9, 9, 21, 22, 15, 13, 15, 9, 15, 6, 15, 13, 6, 9, 13, 22

Solution:

Given data:

12, 21, 21, 3, 9, 3, 6, 12, 13, 21, 15, 22, 3, 6, 9, 9, 21, 22, 15, 13, 15, 9, 15, 6, 15, 13, 6, 9, 13, 22

The discrete frequency distribution table is given as: