
Measure of Central Tendency
Class 9: Mathematics
Arithmetic Mean, Median, Mode, Quartiles, Definitions, Examples, Example Questions with Answer
Arithmetic Mean
Definition: The Mean (or average) of a dataset is the sum of all values divided by the number of values. It is generally represented by
Formulas for Different Series
- Individual Series:
where
- Discrete Series:
where
- Continuous Series:
where
Median
Definition: The Median is the middle value of a dataset when arranged in ascending or descending order. If the dataset has an odd number of values, the median is the middle one. If it has an even number, it is the average of the two middle values. It is generally represented by
Formulas for Different Series
- Individual Series:
Sort the data, and find the middle value:
- If
- If
- Discrete Series:
Arrange data in ascending order and find the cumulative frequency. The median corresponds to the value for which cumulative frequency is
- Continuous Series:
where:
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