Statistics How To

Non Normal Distributions > Logistic Distribution Contents: Stukel Distribution Other logistic distributions What is a Logistic Distribution? The logistic distribution is used for modeling growth, and also for logistic regression. It is a symmetrical distribution, unimodal (it has one peak) and is similar in shape to the normal distribution. In fact, the logistic and normal … Read more

Regression Analysis > Mahalanobis distance What is the Mahalanobis distance? The Mahalanobis distance (MD) is the distance between two points in multivariate space. In a regular Euclidean space, variables (e.g. x, y, z) are represented by axes drawn at right angles to each other; The distance between any two points can be measured with a … Read more

Statistics Definitions > Markov’s Inequality Markov’s Inequality gives an upper bound on the probability that a non negative random variable is greater than or equal to some positive constant. Given a non-negative random variable and a positive constant , Markov’s Inequality states that the probability that is greater than or equal to must be less … Read more

Types of Variables > Polychotomous Variable / Polytomous Variable Contents: Definition Polychotomous Independent Variable Dichotomous vs. Polychotomous Polytomous vs. Polychotomous What is a Polychotomous Variable? A polychotomous variable (also called a polytomous variable) is a variable that can have more than two values (a variable with exactly two values is called a binary variable). Polychotomous variables … Read more

Statistics Definitions > Jackknife Estimator What is a Jackknife Estimator? The jackknife (“leave one out”) can be used to reduce bias and estimate standard errors. It is an alternative to the bootstrap method. Like the bootstrap, the Jackknife involves resampling. The main differences are [1]: The bootstrap involves sampling with replacement many times, while the … Read more

Probability Distributions > Arcsine distribution The arcsine distribution is a symmetric probability distribution with a minimum at x = 1⁄2 and vertical asymptotes at x = 0 and x = 1. Its name comes from the fact that the cumulative distribution function (CDF) involves the arcsine (inverse sine). The probability distribution function (pdf) of the … Read more

Probability and Statistics > Basic Statistics > What is Bias in Statistics? What is Bias in Statistics? Biased Estimators. What is Selection Bias? Survivorship Bias. Social Desirability Bias Acquiescence Bias Availability Bias Other Types of Bias   What is Bias in Statistics? In everyday English, the word “bias” implies having a personal reason to misrepresent … Read more

Probability Distributions > Gompertz-Makeham distribution What is the Gompertz-Makeham Distribution? The Gompertz-Makeham distribution, sometimes called the Makeham distribution, is a generalization of the Gompertz distribution. This continuous probability distribution is a popular model for adult lifetimes, especially in insurance as it can be used to estimate the probability that a person will die within a … Read more

< List of probability distributions < Hypergeometric Distribution Contents: What is the Hypergeometric Distribution? Formula Worked Examples Real Life Uses What is the Hypergeometric Distribution? The hypergeometric distribution is a discrete probability distribution that calculates the probability an event happens k times in n trials when sampling from a small population without replacement. In other … Read more

< Probability Distributions < Limiting Distribution A limiting distribution, also called an asymptotic distribution, is the distribution of a sequence of random variables that converges to a particular distribution as the sample size increases. The term refers to the hypothetical distribution or convergence of a sequence of distributions; It is not a distribution in the … Read more