Statistics How To

Principal Component Analysis > In PCA and Factor Analysis, a variable’s communality is a useful measure for predicting the variable’s value. More specifically, it tells you what proportion of the variable’s variance is a result of either: The principal components or The correlations between each variable and individual factors (Vogt, 1999). In Factor Analysis, communality … Read more

Statistics Definitions > You may want to read this article first: What is an Odds Ratio? What is an Adjusted Odds Ratio? An adjusted odds ratio (AOR) is an odds ratio that controls for other predictor variables in a model. It gives you an idea of the dynamics between the predictors. Multiple regression, which works … Read more

Sampling > What is Area Sampling? Area sampling involves sampling from a map, an aerial photograph, or a similar area frame. It is often the sampling method of choice when a sampling frame isn’t available. For example, a city map can be divided into equal size blocks, from which random samples can be drawn. Although … Read more

Statistics Definitions > The M-estimator is a robust regression method often used as an alternative to the least squares method when data has outliers, extreme observations, or does not follow a normal distribution. While the “M” indicates that M estimation is of the maximum likelihood type (Susanti et. al, 2013), M-estimators are actually a broad … Read more

Statistics Definitions > Prediction error quantifies one of two things: In regression analysis, it’s a measure of how well the model predicts the response variable. In classification (machine learning), it’s a measure of how well samples are classified to the correct category. Sometimes, the term is used informally to mean exactly what it means in … Read more

Statistics Definitions > In general, the term “Operational statistics” refers to a set of statistics that describes operations for a business, organization, or institution. It can also apply to a network, system, or internal operation (for example, a production line). Process The process usually involves: Gathering industry or process specific data, Generating descriptive statistics, Publishing … Read more

Statistics Definitions > Target population is an informal term used mostly in epidemiology. It’s general defined to mean a group or set of elements that you want to know more information about. Most of the time, “target population” and “population” are synonymous. However, adding the word target emphasizes that sometimes we miss the mark in … Read more

Statistics Definitions > Weighting Factor Contents: Weight and the Weighting Factor. Use in Sampling. Use in Nuclear Medicine. Weight Function 1. Weight and the Weighting Factor. A statistical weight is an amount given to increase or decrease the importance of an item. Weights are commonly given for tests and exams in class. For example, a … Read more

Statistics Definitions > What is Extra Sums of Squares? Extra Sums of Squares (ESS) is the difference in the Error Sums of Squares (SSE) of two models. More specifically, ESS is a measure of the marginal reduction in Error Sums of Squares (SSE) when an additional set of predictors is added to the model. It … Read more

Statistics Definitions > Statistical stability is how well the results of your study or experiment hold up. More specifically, it’s a measure of how well you control for random errors in your study. Statistical stability can be defined more precisely for specific fields. For example, let’s say you’re working with signal-to-noise ratio. Josselin Garnier and … Read more