Confused about a term in statistics? Check out our explanations for statistical terms. Statistics definitions in simple English! Many of the statistics definitions you’ll find here include videos, graphs and charts to make the explanations easier to understand.

## Finding What You Need

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## Statistics Definitions in Alphabetical Order

Jump to A B C D E F G H I J K L M N O P Q R S T U V W Y-Z

## A

- 10% Condition
- Adjusted R
- Admissible Decision Rule
- Alpha Level
- Alternate Hypothesis
- ANOVA
- Arithmetic Mean
- Assumption of Independence
- Assumption of Normality
- Average Deviation

## B

- Bell Curve
- Bell’s Numbers
- Beta Level
- Bias
- Bin
- Binomial Coefficient
- Binomial Distribution
- Bivariate Analysis
- Bogardus Scale
- Box and Whiskers Chart
- Bray Curtis Dissimilarity.
- Business Statistics

## C

- Cardinal Numbers
- Causation
- Cauchy-Schwarz Inequality
- Censoring
- Central Tendency
- Chauvenet’s Criterion
- Chebyshev’s Inequality
- Chi-Square Statistic
- Classical Probability
- Classical Test Theory
- Closed form solution
- Cluster Sampling
- Clustered Standard Errors
- Clustering
- Cochran’s Q
- Coefficients.
- Coefficient of Association.
- Coefficient of Determination
- Cohen’s Kappa Statistic
- Cohort Study
- Collinear
- Concordant and Discordant Pairs
- Conditional Distribution
- Conditional Probability
- Confidence Level
- Conservative
- Consistent Estimator
- Construct Validity
- Content Validity
- Contingency Table
- Continuity Correction Factor
- Contour Plot
- Correlation
- Correlation Coefficient Formula
- Correlogram
- Covariance in Statistics
- Cramer-Rao Lower Bound
- Cronbach’s Alpha
- Cumulant Generating Function
- Curvilinear

## D

- Data Analysis
- Data Mining / Data Sets
- Decile
- Density Curve
- Design Effect
- Deterministic
- Dimensionality
- Direction of Association
- Discrete Choice Models
- Discretization
- Dispersion
- Dot Plot
- Durbin Watson Test

## E

- Effect Size
- Empirical Research
- Empirical Rule
- Equivalence Class
- Error Term
- Estimator
- ETA squared
- Expected Value Formula
- Expected Monetary Value
- Experimental Design
- Exploratory Data Analysis
- External Validity
- Extrapolation

## F

- Factor Analysis
- Factorial!
- F Statistic
- False Alarm Ratio
- False Positive and Negative
- Fisher’s Exact Test of Independence
- Fisher Information
- Fisher Z
- Five Number Summary
- Fixed Effects
- Fractile
- Free parameter
- Friedman’s Test
- Frequency Distribution Table
- Frequency Polygon
- Frequentist Statistics

## G

- Gamma Function
- Geodesy
- Geometric Distribution
- Geometric Mean
- Goldfeld Quandt Test
- Gold Standard Test
- Goodness of Fit Test
- Graph Theory
- Greatest Possible Error
- Greedy Matching Algorithm
- Guttman’s Lambda-2

## H

- Harmonic Mean
- Heterogeneous
- Heteroscedasticity
- Hidden Markov Model
- Hierarchical Linear Modeling
- Hierarchical Model.
- Homogeneity
- Hotelling’s T-Squared.
- Hypergeometric Distribution

## I

- IID
- Ill posed problem
- Ill-conditioning.
- Illusory association.
- Imaginary Numbers
- Implicit Factors
- Implicitization
- Inferential Statistics
- Infinitely Divisible
- Integer
- Internal Consistency
- Internal Validity
- Interquartile Range
- Interval Estimate
- Interval Scale
- Inverse Distribution Function
- Inverse Normal
- Item Response Theory

## J

## K

## L

- L-Estimator
- Large Enough Sample Condition
- Latent Semantic Analysis
- Law of Large Numbers
- Least Squares Regression Line
- Levene Test
- Likelihood Function.
- Likelihood Ratio
- Likert Scale
- Line Graph
- Location Parameter
- Logarithms
- Log-Rank test
- Lowess Smoothing

## M

- Mann Whitney U Test
- Marginal Mean
- Market Basket Analysis
- Martingale
- Matched Samples
- McNemar Test
- Mean
- Mean Error
- Mean Squared Error
- Median
- Median Absolute Deviation
- Method of Moments
- Middle Fifty
- Midpoint.
- Midrange
- Minimal Detectable Difference
- Minimum Spanning Tree
- Mode
- Monotonic Relationship
- Monty Hall Problem
- Monte Carlo Simulation
- Morisita Index
- Moving Average
- Moment
- Moment Generating Function
- Multicollinearity
- Multinomial Coefficient
- Multinomial Theorem
- Multiple Imputation
- Multiset
- Multivariate Gamma Function

## N

- Natural Number
- Negative Binomial Experiment
- Nested Model
- Nominal Ordinal Interval Ratio
- NonLinearity
- Non Negative Integer
- Non-Parametric Data and Tests
- Non Centrality Parameter
- Normal Distribution Probability
- Normal Probability Plot
- Null Hypothesis

## O

## P

- P-Value
- Parameter
- Parametric Modeling
- Parametric Tests
- Parameterization.
- Pareto Efficiency.
- Pareto Principle
- Park Test
- Pascal’s Triangle
- Pearson Correlation
- Pearson Mode Skewness
- Pearson’s Coefficient of Skewness
- Percent Error
- Percentiles
- Permuted Block Randomization
- Point Estimate
- Population
- Population Mean
- Population Density
- Population Proportion
- Population variance
- Post-hoc
- Power Law
- Power Mean
- Predictive Analytics
- Prime Numbers
- Principal Component Analysis
- Probabilistic Models
- Probability Density Function
- Probability Distribution
- Probability Distribution Table
- Propensity Score Matching
- Proportion of Variance
- Pygmalion Effect
- Purposive Sampling

## Q

## R

- Random Seed
- Range
- Random Walk
- Rank Biserial
- Rank Histogram
- Rao Blackwell Theorem
- Rate Parameter
- Rate Ratio
- Ratio Scale
- Real Numbers
- Receiver Operating Characteristic Curve
- Regression Equation
- Relative Error
- Relative Precision
- RFM (Customer Value)
- Relative Standard Deviation
- Relative Variance
- Reliability
- Rescaling Data
- Residual values
- Residual Sum of Squares
- Resistant Statistics
- Rician Distribution
- Robust Statistics

## S

- Sample Mean
- Sampling Frame
- Scale Invariance
- Scale Parameter
- Seasonal Kendall Test
- Segmented Bar Chart
- Semantic Differential Scale
- Sensitivity/Specificity
- Serial Correlation
- Sequence Effects
- Shape Parameter
- Shapiro-Wilk Test
- Shifting Data
- Simple linear regression
- Simple Random Sample
- Simpson’s Diversity Index
- Simpson’s Paradox
- Slope Formula
- Slutsky’s Theorem
- Snowball Sampling
- Spearman-Brown Formula
- Standard Deviation
- Standard Error of Measurement
- Standard Error of a Sample
- Standardized Residuals
- Standardized Variables
- Stanine Score
- Stationarity
- Statistic
- Statistical Analysis
- Statistical Conclusion Validity
- Statistical Noise.
- Statistical Power
- Statistical Process Control
- Statistical Relationship
- Statistical Significance
- Statistical Treatment
- STEN Score
- Stratum
- Stratification
- Stress Strength Model
- Student’s T-Test
- Summary Statistics
- Summation Notation
- Survival Analysis

## T

- T Score
- T Statistic
- Test-Retest Reliability
- Test Statistic
- Tikhonov Regularization
- Thurstone Scale
- Transformations
- Treatment-As-Usual
- Trimean
- Trimmed Mean / Truncated Mean
- Turning Point Test
- Tweedie Distribution
- Two Way Table
- Type I and Type II Errors
- Type III and Type IV Errors

## U

## V

## W

- Weighting Factor
- White Test
- Whole Number
- Wilcoxon Signed Rank Sum Test
- Within Mean Square
- Weighted Mean
- W Statistic

## Y/Z

## Style Notes

I try to keep things simple with definitions, using as few words as possible. That’s because these articles are aimed at beginners, or lay people who want an overview. Some people say the articles are *too* simple. If you’re looking for more in depth, head over to Wolfram or Wikipedia. Those places are going to have a lot more formulas, but be prepared to do a bit of translation.

## Why I Started This Site

I remember when I first started learning statistics. I’d look up a term, and what I got was either one sentence (not helpful) or a two page technical manual. Often the words in the manual were ones I didn’t know and they were usually not explained at all. I’d have to go on the hunt for a term and often it would turn into an hours long venture to find what I wanted. What I wanted was simple: an overview of the term so that I could get a general idea of what it was.

Once you’ve got an overview of a topic, then things start to connect in your brain. Things start falling into place. Then you can go back and tackle the in-depth stuff.

I started this site in 2009 and back then, there was little out there in the way of simple explanations. Now it seems there’s a lot of choices from large sites with articles not written by statisticians. That’s where this site is different:

- I’m a statistician, and I’ve taught statistics at the college/university level.
- I’ve got a graduate degree in education, which means I know how to get my point across in a variety of ways. If you don’t like reading, then there’s usually a video. I’m working on videos all the time to add to articles.
- I have struggled with math my whole life. So I know what it’s like to “not get it.” Give me a page of equations and I still get sweaty palms and a churning stomach.
- This site is for YOU, not me, and I love feedback. The bulk of the articles on here were developed in part with feedback and comments.

Check out my YouTube channel for statistics definitions videos!