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Rick WicklinApril 1, 2011 0

Significant changes for SAS blogs

Editor's Note: This article was an April Fool's prank from 2011. The entire article is fake. Today, SAS, the leader in business analytics announces significant changes to two popular SAS blogs, The DO Loop (written by Rick Wicklin) and The SAS Dummy (previously written by Chris Hemedinger). The two blogs

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Angela HallMarch 31, 2011 0

Manage the internal SAS 9.2 account policies

In SAS 9.2, internal accounts can be created and utilized within the metadata and then do not require host (or domain) accounts defined elsewhere. By default, the sasadm@saspw is one such internal account. Unless you specifically declare an exception, the server-level policies for routine password resetting and locking (such as

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Rick WicklinMarch 31, 2011 0

Happy milestone to me: My 100th blog post

This week, I posted the 100th article to The DO Loop. To celebrate, I'm going to analyze the content of my first 100 articles. In December 2010, I compiled a list of The DO Loop's most-read posts, so I won't repeat that exercise. Instead, I thought it would be interesting

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Rick WicklinMarch 30, 2011 0

Ranking with confidence: Part 2

In a previous post, I described how to compute means and standard errors for data that I want to rank. The example data (which are available for download) are mean daily delays for 20 US airlines in 2007. The previous post carried out steps 1 and 2 of the method

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Rick WicklinMarch 28, 2011 0

Changing the length of a character matrix

When you create a character matrix in SAS/IML software, the initial values determine the number of characters that can fit into any element of the matrix. For example, the following statements define a 1x3 character matrix: proc iml; m = {"Low" "Med" "High"}; After the matrix is defined, at most

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Rick WicklinMarch 25, 2011 0

Ranking with confidence: Part 1

I recently posted an article about representing uncertainty in rankings on the blog of the ASA Section for Statistical Programmers and Analysts (SSPA). The posting discusses the importance of including confidence intervals or other indicators of uncertainty when you display rankings. Today's article complements the SSPA post by showing how

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Rick WicklinMarch 23, 2011 0

Indirect assignment: How to create and use matrices named x1, x2,..., xn

I recently blogged about how to eliminate a macro loop in favor of using SAS/IML language statements. The purpose of the program was to extract N 3x3 matrices from a big 3Nx3 matrix. The main portion of my PROC IML program looked something like this: proc iml; ... do i=0

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Angela HallMarch 21, 2011 0

Create a fully summarized table for OLAP Cubes

SAS procedure SUMMARY is a quick method of converting your detail table to a fully summarized one. Included is a sample. The key option to set is the NWAY - this generates the lowest level of summary for use in the OLAP cube. Essentially - the class statement contains all

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Rick WicklinMarch 21, 2011 0

How to create column names for matrices

Statistical programmers can be creative and innovative. But when it comes to choosing names of variables, often x1, x2, x3,... works as well as any other choice. In this blog post, I have two tips that are related to constructing variable names of the form x1, x2,..., xn. Both tips

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Angela HallMarch 18, 2011 0

Star Schema Options in OLAP Cubes

In the past couple months, this scenario has occurred twice. So thought I'd share a quick remedy ~ and save for my future reference when this occurs again :). In Star Schemas, there are sometimes occasions where the data quality isn't exactly perfect. And sometimes, for some users/companies, this is

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Mike GillilandMarch 18, 2011 0

Spring Forecasting Events

We're having an early spring in North Carolina. Trees are budding, flowers are blooming, and the warmer temperatures make even a pistol whipping more enjoyable. What better way to take advantage of the new season than filling your spring with educational opportunities in forecasting. Plan in Perfect Sync with Customer

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Rick WicklinMarch 18, 2011 0

An analysis of subjects in The Far Side cartoons

Loony. Zany. Brilliant. Hysterical. Those are some of the adjectives I use to describe The Far Side® cartoons by Gary Larson from the 1980s and early '90s. I recently rediscovered an old book, The Far Side Gallery 2, which collects some of the best of Larson's wonderfully wacky cartoons. Every

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Rick WicklinMarch 16, 2011 0

Sorting a matrix by row or column statistics

In a previous blog post, I showed how to use the SAS/IML SORT and SORTNDX subroutines to sort rows of a matrix according to the values of one or more columns. There is another common situation in which you might need to sort a matrix: you compute a statistic for

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Rick WicklinMarch 14, 2011 0

Sorting rows of a matrix

Sorting is a fundamental operation in statistical programming, and most SAS programmers are familiar with PROC SORT for sorting data sets. But did you know that you can also sort rows of a SAS/IML matrix according to the value of one or more columns? This post shows how. Sorting a

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Angela HallMarch 12, 2011 0

Adding Negative Solve Orders to OLAP Calculated Members

OLAP Calculated Members need to be tested to ensure that the numbers are correct in various tools. What we recently found was that the member tested properly in the OLAP Studio View Cube but then in Web Report Studio, the measure wasn't correct. Essentially, it was calculating the custom measurement

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Rick WicklinMarch 11, 2011 0

Simulating a random walk

In my spare time, I enjoy browsing the StackOverflow discussion forum to see what questions people are asking about SAS, SAS/IML, and statistics. Last week, a statistics student asked for help with the following homework problem: I need to generate a one-dimensional random walk in which the step length and

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Rick WicklinMarch 9, 2011 0

Cuzick's Test for Trend: A case study in translating a MATLAB program into the SAS/IML language

Several times a year, I am contacted by a SAS account manager who tells me that a customer has asked whether it is possible to convert a MATLAB program to the SAS/IML language. Often the customer has an existing MATLAB program and wants to include the computation as part of

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Rick WicklinMarch 7, 2011 0

Need case-insensitive string comparisons? UPCASE!

String comparisons in SAS software are case-sensitive. For example, the uppercase letter "F" and lowercase letter "f" are treated as unique characters. When these two letters represent the same condition (for example, a female patient), the strings need to be handled in a case-insensitive manner, and a SAS programmer might

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Rick WicklinMarch 4, 2011 0

How to use transparency to overcome overplotting

Do you have many points in your scatter plots that overlap each other? If so, your graph exhibits overplotting. Overplotting occurs when many points have similar coordinates. For example, the following scatter plot (which is produced by using the ODS statistical graphics procedure, SGPLOT) displays 12,000 points, many of which

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Rick WicklinMarch 2, 2011 0

The macro loop that vanished: How to simplify your SAS/IML programs

I don't use the SAS macro language very often. Because the SAS/IML language has statements for looping and evaluating expressions, I rarely write a macro function as part of a SAS/IML programs. Oh, sure, I use the %LET statement to define global constants, but I seldom use the %DO and

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Rick WicklinFebruary 28, 2011 0

Simulation and sampling in Las Vegas

If you haven't signed up for SAS Global Forum 2011 in Las Vegas, you'd better get moving: February 28 is the last day for early registration and the discounted hotel prices. You should also sign up for the pre-conference statistical tutorials, which are filling up fast! I was tempted to

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Mike GillilandFebruary 25, 2011 0

When Executive Managment Hurts

As we discussed last week, the forecasting process is often contaminated by individuals whose input makes the forecast worse. Sometimes this is intentional. For example, if I'm tired of hearing customers complain about out-of-stocks on retail shelves, I'll try to drive up the forecast so that more inventory will be

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Rick WicklinFebruary 25, 2011 0

Bias and covariance explained to an 11-year-old

I was inspired by Chris Hemedinger's blog posts about his daughter's science fair project. Explaining statistics to a pre-teenager can be a humbling experience. My 11-year-old son likes science. He recently set about trying to measure which of three projectile launchers is the most accurate. I think he wanted to

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Rick WicklinFebruary 23, 2011 0

SAS/IML operations compared with PROC SQL: Part 1

I don't know much about the SQL procedure, but I know that it is powerful. According to the SAS documentation for the SQL procedure, "PROC SQL can perform some of the operations that are provided by the DATA step and the PRINT, SORT, and SUMMARY procedures." Recently, a fellow blogger,

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Angela HallFebruary 21, 2011 0

Super Important Tip on Upgrading from 4.2 to 4.2 Add-in to MS Office

When upgrading from an existing 4.2 client install of SAS Add-in to MS Office, you are not prompted to enable the Outlook portion of the Add-in. As SAS points out in the KB Post http://support.sas.com/kb/40/272.html, there is a 'Switcher Utility' available in the client install. When running this, I would

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Rick WicklinFebruary 21, 2011 0

How to build a vector from expressions

If you are a statistical programmer, sooner or later you have to compute a confidence interval. In the SAS/IML language, some beginning programmers struggle with forming a confidence interval. I don't mean that they struggle with the statistics (they know how to compute the relevant quantities), I mean that they

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Mike GillilandFebruary 18, 2011 0

Forecasting or Golf?

A recurring theme of The Business Forecasting Deal (both this blog and the book) is that forecasting is a huge waste of management time. This doesn't mean that forecasting is pointless, irrelevant, or entirely useless in running our organizations. It only means that the amount of time, money, and human

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Rick WicklinFebruary 18, 2011 0

Comedy vs. Drama: A comparative histogram of TV's top earners

The Flowing Data blog posted some data about how much TV actors get paid per episode. About a dozen folks have created various visualizations of the data (see the comments in the Flowing Data blog), several of them very glitzy and fancy. One variable in the data is a categorical

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Rick WicklinFebruary 16, 2011 0

Converting matrix subscripts to indices

Suppose that you want to create a matrix in SAS/IML software that has a special structure, such as a tridiagonal matrix. How do you do it? Or suppose that you want to find elements of a matrix A such that A[i,j] satisfies a certain condition. How do you get the

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Rick WicklinFebruary 14, 2011 0

A parametric view of love

If you tell my wife that she's married to a statistical geek, she'll nod knowingly. She is used to hearing sweet words of affection such as You are more beautiful than Euler's identity. or My love for you is like the exponential function: increasing, unbounded, and transcendental. But those are

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