Measures of Central Tendency

Core concept

For grouped data, mean can be calculated using the direct method (sum of frequency×midpoint, divided by total frequency), the assumed mean method (simplifying calculation by measuring deviations from an assumed central value), or the step-deviation method (further simplifying by dividing deviations by a common class width). Each measure has different strengths: mean is sensitive to extreme outlier values, while median and mode are more resistant to being skewed by unusually large or small values in the data set.