Explain the meaning of the following terms:

(1) Variate

Any character that can vary from one individual to another is called variate.

(2) Class interval

In the data each group into which raw data is considered is called a class-interval.

(3) Class-size

The difference between the true upper limit and lower limit is called the class size of that class size.

(4) Class-mark

The middle value of the class is called as the class mark.

Class Mark $=\frac{\text { Upper Limit }+\text { Lower Limit }}{2}$

(5) Frequency

The number of observations corresponding to class is called its frequency.

(6)Class limits

Each class is bounded by two figures ,called the class limits .The figures on the left side of the classes are called lower limits while figures on the right side are called upper limits.

(7)True class limits

If classes are inclusive.Eg: 15 - 19, 20 - 24, 25 - 29….

Then, true lower limit of class = Upper Limit of Class - 0.5

Eg:- True limits of the class is 15 - 19 are 14.5 and 19.5

But if classes are exclusive like 10 - 20, 20 - 30, 30 - 40…

Here class limits and true class limits are the same.