## Difference operators as matrices

For a time series { y1, y2, ..., yN }, the difference operator computes the…

By Rick Wicklin 0

For a time series { y1, y2, ..., yN }, the difference operator computes the…

By Rick Wicklin 2

Rotation matrices are used in computer graphics and in statistical analyses. A rotation matrix is…

By Rick Wicklin 10

Every year near Halloween I write an article in which I demonstrate a simple programming…

By Rick Wicklin 2

What is weighted regression? How does it differ from ordinary (unweighted) regression? This article describes…

By Rick Wicklin 5

Last week I showed how to represent a Markov transition matrix in the SAS/IML matrix…

By Rick Wicklin 4

Many computations in elementary probability assume that the probability of an event is independent of…

By Rick Wicklin 0

A grid is a set of evenly spaced points. You can use SAS to create…

By Rick Wicklin 2

Children in primary school learn that every positive number has a real square root. The…

By Rick Wicklin 0

Last week I attended SAS Global Forum 2016 in Las Vegas. I and more than…

By Rick Wicklin 12

Last week I showed how to create dummy variables in SAS by using the GLMMOD…