Statistics How To

Effect Size > Hedges’ g What is Hedges’ g? Watch the video, or read on below. Can’t see the video? Click here to watch it on YouTube. Hedges’ g is a measure of effect size. Effect size tells you how much one group differs from another—usually a difference between an experimental group and control group. … Read more

Factor Analysis > Kaiser-Meyer-Olkin (KMO) Test What is the Kaiser-Meyer-Olkin (KMO) Test? Watch the video or read on below. Can’t see the video? Click here to view it on YouTube. The Kaiser-Meyer-Olkin (KMO) Test is a measure of how suited your data is for Factor Analysis. The test measures sampling adequacy for each variable in … Read more

Post Hoc Tests > Benjamini-Hochberg Procedure What is the Benjamini-Hochberg Procedure? Watch the video or read on below. Can’t see the video? Click here to view it on YouTube. The Benjamini-Hochberg Procedure is a powerful tool that decreases the false discovery rate. Adjusting the rate helps to control for the fact that sometimes small p-values … Read more

Correlation Coefficients > Tetrachoric Correlation What is Tetrachoric Correlation? Watch the video, or read on below. Can’t see the video? Click here to watch it on YouTube. Tetrachoric correlation estimates the association between two underlying continuous variables that have been dichotomized into binary outcomes (e.g., yes/no, correct/incorrect), assuming those latent variables (which are hidden variables … Read more

Types of Variable > Random Variable Contents: What is a Random Variable? Discrete and Continuous Random Variables Random Events: Examples Probabilities Mean and Mode of a Random Variable Variance: Discrete Random Variable Continuous Random Variable Binomial Random Variable PDF and CDF Random Variate See also: Independent Random Variables. What is a Random Variable? In algebra … Read more

Probability > Maximum Likelihood What is Maximum Likelihood? Maximum Likelihood picks parameters of the function under which your data are most likely. In elementary statistics, you are usually given a model to find probabilities. For example, you might be asked to find the probability that X is greater than 2, given the following Poisson distribution: … Read more

Basic Statistics > What is a Parameter in Statistics? What is a Parameter in Statistics? A parameter is a numerical characteristic of a population, and it is measured from the population. It is any summary number, such as mean or percentage, that describes the entire population. In comparison, a statistic is a numerical characteristic of … Read more

Statistics Definitions > Beta Level What is a Beta Level?   Alpha levels and beta levels are related: An alpha level is the probability of a type I error, or rejecting the null hypothesis when it is true. A beta level, usually just called beta(β), is the opposite*; the probability of of accepting the null … Read more

> Probability > Mutually Independent and Pairwise Independent Contents: What is Pairwise? Averages (Walsh Averages) Comparison Differences Independent / Mutually Independent. Statistics Slopes What is Pairwise? Pairwise means to form all possible pairs — two items at a time — from a set. For example, in the set {1,2,3} all possible pairs are (1,2), (2,3), … Read more

> Statistics Definitions > Population Mean Contents: What is the population mean? Formula and Example Sample mean vs. population mean Graph showing population mean (μ) and standard deviation of age at first marriage [1].   What is the population mean? The population mean represents the average of a characteristic within a specific group, which could … Read more