Explanatory model - An explanatory model represents an outcome as related to one or more other variables.
Exponential dispersion model - An exponential dispersion model is a family of probability distributions whose density or probability mass function separates a natural parameter from a...
Exponential-logarithmic distribution - The exponential-logarithmic distribution is a continuous probability distribution for positive lifetimes, formed by combining exponential failure times with...
Extensive sampling - Extensive sampling describes sampling that emphasizes broad coverage across geography, subject matter, or time rather than concentrated investigation of a...
F distribution - The F distribution is a continuous probability distribution obtained by taking the ratio of two independent chi-square random variables, each divided by its...
F-test of equality of variances - The F-test of equality of variances is a classical hypothesis test comparing the population variances underlying two independent normal samples.
Face-to-face survey - A face-to-face survey collects responses through an interviewer and respondent meeting in person.
Factor level - A factor level is a particular value or category of an input variable studied in an experiment. If temperature is a factor, 60°C and 80°C can be two levels.
Factor range - Factor range is the difference between the highest and lowest values of a quantitative factor used in an experimental design.
Factorial design - A factorial design is an experimental arrangement that studies two or more factors together by combining their levels.
Failure bias - Failure bias is an informal label for drawing general conclusions from visible failures while overlooking relevant successes or other cases that did not fail.
Failure rate - Failure rate, in lifetime analysis, is the instantaneous rate at which units fail conditional on having survived to a given time.
False discovery rate - The false discovery rate, or FDR, is the expected proportion of rejected null hypotheses that are actually true.
Familywise error rate - Familywise error rate, or FWER, is the probability of rejecting at least one true null hypothesis within a specified family of hypothesis tests.
Fan chart (time series) - A fan chart is a time-series visualization that displays a central forecast together with nested probability bands for future outcomes.
Fast probability integration - Fast probability integration, or FPI, refers to efficient numerical approaches for evaluating probabilities defined by uncertain model inputs and a...
Field experiment - A field experiment evaluates an intervention in a setting that reflects real-world activity rather than only an artificial laboratory task.
Firmographics - Firmographics are descriptive attributes used to characterize and group organizations, such as industry, size, location, age and organizational structure.
First-hitting-time model - A first-hitting-time model describes an event time as the first moment a stochastic process reaches a specified boundary or set.
First order interaction - A first order interaction is an interaction between two variables: the relationship between one variable and an outcome depends on the level of the other.
First-order reliability method - The first-order reliability method, or FORM, estimates a threshold-event probability by approximating a limit-state boundary with a tangent hyperplane at a...
First-order second-moment method - The first-order second-moment method, often abbreviated FOSM, approximates the mean and variance of a model output using a first-order Taylor expansion and...
Fisher exact test - The Fisher exact test assesses association in a contingency table using a probability distribution conditional on the table's margins.
Fisher's inequality - Fisher's inequality is a necessary condition for a nontrivial balanced incomplete block design: the number of blocks b must be at least the number of...
Fisher's least significant difference - Fisher's least significant difference is a threshold and associated procedure for comparing two means using an error variance pooled from an...
Fisher's Least Significant Difference Test (LSD) - Fisher's Least Significant Difference Test, abbreviated LSD, is a pairwise mean-comparison procedure using a common error estimate from an...
Fisher's method - Fisher's method combines several p-values into one test statistic by summing their negative logarithms.
Fixed marginal totals - Fixed marginal totals are row or column totals in a contingency table that are held constant by the sampling or allocation design, rather than varying...
Fixed model Anova - Fixed model Anova refers to analysis of variance in which the factor levels are treated as fixed effects: the analysis concerns the particular levels...
Fixed sample - A fixed sample, in the repeated-survey sense used here, consists of the same selected units observed on successive occasions.
Fixed variable - A fixed variable, in the experimental-design sense used here, is an independent variable whose particular levels are specified by the researcher.
Fligner-Killeen test - The Fligner-Killeen test is a rank-based procedure used to investigate whether independent groups have a common population spread, commonly described as a...
Flow sampling - Flow sampling, in duration analysis, selects units through transitions occurring during a defined time interval.
Flow series - A flow series is a time series whose observations measure activity over specified periods, rather than a quantity at a single instant.
Focus groups - Focus groups are moderated discussions in which a small group of participants explores a defined topic through questions, responses and interaction with one...
Forecast attainment - Forecast attainment is an operational comparison of an actual outcome with the forecast prepared for that outcome.
Forecast bias - Forecast bias is a systematic tendency for predictions to be too high or too low relative to the quantity they are intended to forecast.
Forecast skill - Forecast skill describes how well a forecasting system predicts compared with a specified reference or benchmark, under a defined evaluation method.
Forking paths problem - The forking paths problem arises when analytical choices depend on the observed data, but the final statistical result is interpreted as though the entire...
Fractiles - Fractiles are values that locate specified fractions of a distribution, including quartiles, deciles and percentiles.
Fractional factorial design - A fractional factorial design is an experimental design that uses a carefully selected subset of the treatment combinations in a full factorial experiment.
Fractional model - A fractional model is a statistical model for an outcome expressed as a fraction or proportion, usually between zero and one.
Frequency distribution - A frequency distribution organizes observations by how often their values or categories occur.
Frequentist statistical inference - Frequentist statistical inference uses data to estimate or test properties of a population or process through procedures evaluated by their behavior under...
Friedman test - The Friedman test is a rank-based test for comparing three or more related conditions in a complete-block or repeated-measures design.
Frisch - Waugh - Lovell theorem - The Frisch-Waugh-Lovell theorem is an exact algebraic result for ordinary least squares regression.
Full joint probability distribution - A full joint probability distribution specifies the probabilities of all combinations of values for all random variables included in a probability model.
Functional regression - Functional regression models relationships in which an outcome, a predictor or both are functions, such as curves observed over time, wavelength or space.