Statistics Formulas
Key statistics formulas for mean, median, standard deviation, probability, and regression.
Understand data analysis with clear explanations and examples.
Basic Probability Formula
Calculate probability with P(A) = favorable outcomes / total outcomes. The foundation of all probability and statistics.
Bayes' Theorem
Apply Bayes' Theorem with P(A|B) = P(B|A) × P(A) / P(B). Update probabilities based on new evidence and conditional information.
Correlation Coefficient Formula
Calculate the Pearson correlation coefficient r to measure the strength and direction of a linear relationship between two variables.
Linear Regression Formula
Calculate the line of best fit with y = mx + b. Predict outcomes using linear regression and understand the slope and intercept.
Mean (Average) Formula
Calculate the arithmetic mean with Mean = Σx / n. The most common way to find the central value of a data set.
Median Formula
Find the median of a data set. The median is the middle value when data is sorted. Learn how to handle both odd and even data sets.
Normal Distribution Formula
Understand the normal distribution (bell curve) with f(x) = (1/σ√(2π)) × e^(-(x-μ)²/(2σ²)). The most important distribution in statistics.
Standard Deviation Formula
Calculate standard deviation with σ = √(Σ(x - μ)² / N). Measure how spread out values are from the mean in any data set.
Variance Formula
Calculate variance with σ² = Σ(x - μ)² / N. Understand how much data values deviate from the mean on average.
Z-Score Formula
Calculate the z-score with z = (x - μ) / σ. Find how many standard deviations a value is above or below the mean.