The DO Loop
Statistical programming in SAS with an emphasis on SAS/IML programs
The graph to the right is the quantile function for the standard normal distribution, which is sometimes called the probit function. Given any probability, p, the quantile function gives the value, x, such that the area under the normal density curve to the left of x is exactly p. This
Oh, no! Your boss just told you to change the way that SAS displays certain features in graphs, such as missing values. But you have a library of hundreds of SAS programs! Do you need to modify all of your previous programs? Fortunately, the answer is no. SAS provides ODS
In an article about how to visualize missing data in a heat map, I noted that the SAS SG procedures (such as PROC SGPLOT) use the GraphMissing style element to color a bar or tile that represents a missing value. In the HTMLBlue ODS style, the color for missing values
Longitudinal data are measurements for a set of subjects at multiple points in time. Also called "panel data" or "repeated measures data," this kind of data is common in clinical trials in which patients are tracked over time. Recently, a SAS programmer asked how to visualize missing values in a
This article shows how to compute properties of a discrete probability distribution from basic definitions. You can use the definitions to compute the mean, variance, and median of a discrete probability distribution when there is no simple formula for those quantities. This article is motivated by two computational questions about
Statistical programmers need to access numerical constants that help us to write robust and accurate programs. Specifically, it is necessary to know when it is safe to perform numerical operations such as raising a number to a power without exceeding the largest number that is representable in finite-precision arithmetic. This