Tag: Getting Started

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Rick Wicklin 0
Grids and linear subspaces

A grid is a set of evenly spaced points. You can use SAS to create a grid of points on an interval, in a rectangular region in the plane, or even in higher-dimensional regions like the parallelepiped shown at the left, which is generated by three vectors. You can use

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Rick Wicklin 0
Create a package in SAS/IML

In a previous post I showed how to download, install, and use packages in SAS/IML 14.1. SAS/IML packages incorporate source files, documentation, data sets, and sample programs into a ZIP file. The PACKAGE statement enables you to install, uninstall, and manage packages. You can load functions and data into your

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Rick Wicklin 0
Create dummy variables in SAS

A dummy variable (also known as indicator variable) is a numeric variable that indicates the presence or absence of some level of a categorical variable. The word "dummy" does not imply that these variables are not smart. Rather, dummy variables serve as a substitute or a proxy for a categorical

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Rick Wicklin 0
What is a moving average?

A moving average (also called a rolling average) is a statistical technique that is used to smooth a time series. Moving averages are used in finance, economics, and quality control. You can overlay a moving average curve on a time series to visualize how each value compares to a rolling

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Rick Wicklin 0
Compute a weighted mean in SAS

Weighted averages are all around us. Teachers use weighted averages to assign a test more weight than a quiz. Schools use weighted averages to compute grade-point averages. Financial companies compute the return on a portfolio as a weighted average of the component assets. Financial charts show (linearly) weighted moving averages

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Rick Wicklin 0
Those tricky PERCENT formats

When using SAS to format a number as a percentage, there is a little trick that you need to remember: the width of the formatted value must include room for the decimal point, the percent sign, and the possibility of two parentheses that indicate negative values. The field width must

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Rick Wicklin 0
Convert a vector to a string

Base SAS contains many functions for processing strings, and you can call these functions from within a SAS/IML program. However, sometimes a SAS/IML programmer needs to process a vector of strings. No problem! You can call most Base SAS functions with a vector of parameters. I have previously written about

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Rick Wicklin 0
IF-THEN logic with matrix expressions

In the SAS DATA step, all variables are scalar quantities. Consequently, an IF-THEN/ELSE statement that evaluates a logical expression is unambiguous. For example, the following DATA step statements print "c=5 is TRUE" to the log if the variable c is equal to 5: if c=5 then put "c=5 is TRUE";

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Rick Wicklin 0
What is an empty matrix?

At the beginning of my book Statistical Programming with SAS/IML Software I give the following programming tip (p. 25): Do not confuse an empty matrix with a matrix that contains missing values or with a zero matrix. An empty matrix has no rows and no columns. A matrix that contains

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