Calculate mean, median, mode, range, standard deviation, variance, geometric & harmonic mean and more — with step-by-step solutions.
The arithmetic mean (average) is sensitive to outliers — a single extreme value can skew it dramatically. The median (middle value) is robust to outliers and better represents the "typical" value in skewed distributions like income data.
Standard deviation measures the spread of numbers around the mean. A low SD means values are clustered closely; a high SD means they are spread out. Population SD divides by n; sample SD divides by (n−1) to correct for estimation bias.
The geometric mean is ideal for averaging rates of change, ratios, or percentages (like investment returns). It is calculated as the nth root of the product of all values. All values must be positive for a real result.
A weighted average assigns different levels of importance to each value. Common uses include GPA calculation (credit hours as weights), price indices, and survey responses. Formula: Σ(value × weight) / Σweight.