# Continuous Series Data

In which entire available data is divided into equal intervals. Each group represents different values but with same range. Formulas for calculating Arithmetic mean

Direct Method:

Shortcut method without step deviation:

Shortcut method with step deviation:

In continuous series x is middle value for each class. x =

where is lower limit and is upper limit.

And C is Class interval.

Example: Find out Arithmetic mean for the given data.

 x (marks) F (no. of students)

### Direct Method:

 Class interval x = f fx = 300

.

### Shortcut Method:

Without Step deviation:

 Class interval x = f dx = x-A fdx = 300

With Step deviation:

 Class interval x = f dx = x-A dx’ = dx/C fdx’

## Precautions of Using Arithmetic Mean:

• Arithmetic Mean is a theoretical value which may not represent actual fact.

Ex: Average children per family would be 2.3 but it is unrealistic. There would be either 2 children or 3 children per family. Note: There is a possibility for no children in some families.

• Arithmetic Mean cannot be calculated for qualitative data such as honesty, beauty etc.

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