Mean (Arithmetic Mean)
Definition
The sum of all observations divided by the total number of observations. It is the most commonly used measure of central tendency. Formula: x̄ = Σx / n. It is affected by extreme values (outliers).
Example
"Marks of 5 students: 60, 70, 80, 90, 100. Mean = (60+70+80+90+100)/5 = 400/5 = 80."