The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs![The stationary block bootstrap in SAS](https://blogs.sas.com/content/iml/files/2021/01/StationaryBoot1-640x336.png)
This is the third and last introductory article about how to bootstrap time series in SAS. In the first article, I presented the simple block bootstrap and discussed why bootstrapping a time series is more complicated than for regression models that assume independent errors. Briefly, when you perform residual resampling
![The DOLIST syntax: Specify a list of numerical values in SAS](https://blogs.sas.com/content/iml/files/2021/01/DOList2-640x336.png)
Have you ever heard of the DOLIST syntax? You might know the syntax even if you are not familiar with the name. The DOLIST syntax is a way to specify a list of numerical values to an option in a SAS procedure. Applications include: Specify the end points for bins
![The moving block bootstrap for time series](https://blogs.sas.com/content/iml/files/2021/01/movingBoot1-702x240.png)
As I discussed in a previous article, the simple block bootstrap is a way to perform a bootstrap analysis on a time series. The first step is to decompose the series into additive components: Y = Predicted + Residuals. You then choose a block length (L) that divides the total
![Blog posts from 2020 that deserve a second look](https://blogs.sas.com/content/iml/files/2017/01/ProgrammingTips-2.png)
On The DO Loop blog, I write about a diverse set of topics, including statistical data analysis, machine learning, statistical programming, data visualization, simulation, numerical analysis, and matrix computations. In a previous article, I presented some of my most popular blog posts from 2020. The most popular articles often deal
![The simple block bootstrap for time series in SAS](https://blogs.sas.com/content/iml/files/2021/01/simpleBlockBoot6-702x336.png)
For ordinary least squares (OLS) regression, you can use a basic bootstrap of the residuals (called residual resampling) to perform a bootstrap analysis of the parameter estimates. This is possible because an assumption of OLS regression is that the residuals are independent. Therefore, you can reshuffle the residuals to get
![Top posts from The DO Loop in 2020](https://blogs.sas.com/content/iml/files/2020/03/cumul6-500x336.png)
Last year, I wrote more than 100 posts for The DO Loop blog. In previous years, the most popular articles were about SAS programming tips, statistical analysis, and data visualization. But not in 2020. In 2020, when the world was ravaged by the coronavirus pandemic, the most-read articles were related