Statistics Calculator

• Mean — the average; sensitive to extreme values (outliers)
• Median — the middle value; robust to outliers; better for skewed data like income
• Mode — the most frequent value; useful for categorical or discrete data
• Standard deviation — how spread out the values are; low = clustered near mean, high = widely spread

When your data is the entire population, divide by N for variance. When it's a sample from a larger group, divide by N−1 (Bessel's correction) to get an unbiased estimate. Most real-world statistics work uses sample standard deviation (÷ N−1).

For income, housing prices, or any data with outliers, the median is more representative. A neighborhood where nine houses cost $300,000 and one costs $3,000,000 has a mean of $570,000 — misleading. The median is $300,000, which better reflects the typical house.