Category Archives: Word of the Week

In a classification model, the confusion matrix shows the counts of correct and erroneous classifications.  In a binary classification problem, the matrix consists of 4 cells.

The predictors in a predictive model are sometimes given different terms by different disciplines.  Traditional statisticians think in terms of variables.

Structured data is data that is in a form that can be used to develop statistical or machine learning models (typically a matrix where rows are records and columns are variables or features).

Censoring in time-series data occurs when some event causes subjects to cease producing data for reasons beyond the control of the investigator, or for reasons external to the issue being studied.

Predictive modeling is the process of using a statistical or machine learning model to predict the value of a target variable (e.g. default or no-default) on the basis of a series of predictor variables (e.g. income, house value, outstanding debt, etc.).

Goodness-of-fit measures the difference between an observed frequency distribution and a theoretical probability distribution which

An adjacency matrix describes the relationships in a network. Nodes are listed in the top..

In a test of significance (also called a hypothesis test), Type I error is the error of rejecting the null hypothesis when it is true — of saying an effect or event is statistically significant when it is not.

Data partitioning in data mining is the division of the whole data available into two or three non-overlapping sets: the training set (used to fit the model), the validation set (used to compared models), and the test set (used to predict performance on new data).

Longitudinal data records multiple observations over time for a set of individuals or units. A typical..

Cross-sectional data refer to observations of many different individuals (subjects, objects) at a given time, each observation belonging to a different individual.  A simple…

CHAID stands for Chi-squared Automatic Interaction Detector. It is a method for building classification trees and regression trees from a training sample comprising already-classified objects.

Also called the training sample, training set, calibration sample.  The context is predictive modeling (also called supervised data mining) –  where you have data with multiple predictor variables and a single known outcome or target variable.

The centroid is a measure of center in multi-dimensional space.

Promoting better understanding of statistics throughout the world.

New Editor of Journal of Statistics Education

Read Peter’s Letter to the Editor in Saturday’s Washington Post.

Last year’s popular story out of the Predictive Analytics World conference series was Andrew Pole’s presentation of Target’s methodology for predicting which customers were pregnant.

Evidence show that there is no significant difference between taking an online introductory statistics course and a traditional in-person class.

Facebook began trading around 11:30 this morning, and I spent 8 minutes