Free reference · 596 entries
The words, before the course.
Short, plain definitions of the terms that turn up in statistics and data science — what they mean, and how they relate to each other. Nothing to sign in for.
21 of 596 entries under E
- EconometricsEconometrics is a discipline concerned with the application of statistics and mathematics to various problems in economics and economic theory.
- EdgeAn edge is a link between two people or entities in a network. Edges can be directed or undirected.
- EffectIn design of experiments, the effect of a factor is an additive term of the model, reflecting the contribution of the factor to the response.
- Effect SizeIn a study or experiment with two groups (usually control and treatment), the investigator typically has in mind the magnitude of the difference between the two groups that he or she wants to be able to…
- EfficiencyFor an unbiased estimator, efficiency indicates how much its precision is lower than the theoretical limit of precision provided by the Cramer-Rao inequality.
- Endogenous VariableEndogenous variables in causal modeling are the variables with causal links (arrows) leading to them from other variables in the model.
- Ensemble MethodsIn predictive modeling, ensemble methods refer to the practice of taking multiple models and averaging their predictions.
- Erlang DistributionThe Erlang distribution with parameters (n, m) characterizes the distribution of time intervals until the emergence of n events in a Poisson process with parameter m .
- ErrorError is a general concept related to deviation of the estimated quantity from its true value: the greater the deviation, the greater the error.
- Error Spending FunctionSee alpha spending function.
- EstimationEstimation is deriving a guess about the actual value of a population parameter (or parameters) from a sample drawn from this population.
- EstimatorA statistic, measure, or model, applied to a sample, intended to estimate some parameter of the population that the sample came from.
- EventIn probability theory, an event is an outcome or defined collection of outcomes of a random experiment.
- Exact TestsExact tests are hypothesis tests that are guaranteed to produce Type-I error at or below the nominal alpha level of the test when conducted on samples drawn from a null model.
- Exogenous VariableExogenous variables in causal modeling are the variables with no causal links (arrows) leading to them from other variables in the model.
- Expected ValueThe expected value of a random variable is nothing but the arithmetic mean. For a discrete random variable, the expected value is the weighted average of the possible values of the random variable, the…
- ExperimentAny process of observation or measurement is called an experiment in statistics. For example, counting the number people visiting a restaurant in a day is an experiment, and so is checking the number…
- Explanatory VariableExplanatory variable is a synonym for independent variable.
- Exponential DistributionThe exponential distribution is a one-sided distribution completely specified by one parameter r > 0; the density of this distribution is re–rx, x ³ 0 0, x < 0 The mean of the exponential distribution is…
- Exponential Distribution (Graphical)The exponential distribution is a one-sided distribution completely specified by one parameter ; the density of this distribution is The mean of the exponential distribution is .
- Exponential FilterThe exponential filter is the simplest linear recursive filter. Exponential filters are widely used in time series analysis, especially for forecasting time series (see the short course Time Series…
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