Posts Tagged ‘ Getting Started ’

What is rank correlation?

August 14, 2017
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What is rank correlation?

When someone refers to the correlation between two variables, they are probably referring to the Pearson correlation, which is the standard statistic that is taught in elementary statistics courses. Elementary courses do not usually mention that there are other measures of correlation. Why would anyone want a different estimate of [...] The post What is rank correlation? appeared first on The DO Loop.

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The IFN function versus the IF-THEN/ELSE statement in SAS

June 7, 2017
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The IFN function versus the IF-THEN/ELSE statement in SAS

I have previously discussed how to define functions that safely evaluate their arguments and return a missing value if the argument is not in the domain of the function. The canonical example is the LOG function, which is defined only for positive arguments. For example, to evaluate the LOG function [...] The post The IFN function versus the IF-THEN/ELSE statement in SAS appeared first on The DO Loop.

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A simple trick to construct symmetric intervals

April 10, 2017
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A simple trick to construct symmetric intervals

Many intervals in statistics have the form p ± δ, where p is a point estimate and δ is the radius (or half-width) of the interval. (For example, many two-sided confidence intervals have this form, where δ is proportional to the standard error.) Many years ago I wrote an article [...] The post A simple trick to construct symmetric intervals appeared first on The DO Loop.

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LEAVE and CONTINUE: Two ways to control the flow in a SAS DO loop

March 15, 2017
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LEAVE and CONTINUE: Two ways to control the flow in a SAS DO loop

SAS programmers who have experience with other programming languages sometimes wonder whether the SAS language supports statements that are equivalent to the "break" and "continue" statements in other languages. The answer is yes. The LEAVE statement in the SAS DATA step is equivalent to the "break" statement. It provides a [...] The post LEAVE and CONTINUE: Two ways to control the flow in a SAS DO loop appeared first on…

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An easy way to run thousands of regressions in SAS

February 13, 2017
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An easy way to run thousands of regressions in SAS

A common question on SAS discussion forums is how to repeat an analysis multiple times. Most programmers know that the most efficient way to analyze one model across many subsets of the data (perhaps each country or each state) is to sort the data and use a BY statement to [...] The post An easy way to run thousands of regressions in SAS appeared first on The DO Loop.

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ODS OUTPUT: Store any statistic created by any SAS procedure

January 9, 2017
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ODS OUTPUT: Store any statistic created by any SAS procedure

In the beginning SAS created procedures and output. The output was formless and void. Then SAS said, "Let there be ODS," and there was ODS. Customers saw that ODS was good, and SAS separated the computation from the display and management of output. The preceding paragraph oversimplifies the SAS Output […] The post ODS OUTPUT: Store any statistic created by any SAS procedure appeared first on The DO Loop.

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Solve linear programming problems in SAS

December 19, 2016
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Solve linear programming problems in SAS

In some applications, you need to optimize a linear objective function of many variables, subject to linear constraints. Solving this problem is called linear programming or linear optimization. This article shows two ways to solve linear programming problems in SAS: You can use the OPTMODEL procedure in SAS/OR software or […] The post Solve linear programming problems in SAS appeared first on The DO Loop.

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Use SAS formats to bin numerical variables

August 8, 2016
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Use SAS formats to bin numerical variables

SAS formats are flexible, dynamic, and have many uses. For example, you can use formats to count missing values and to change the order of a categorical variable in a table or plot. Did you know that you can also use SAS formats to recode a variable or to bin […] The post Use SAS formats to bin numerical variables appeared first on The DO Loop.

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Statistical model building and the SELECT procedures in SAS

July 25, 2016
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Statistical model building and the SELECT procedures in SAS

Last week I read an interesting paper by Bob Rodriguez: "Statistical Model Building for Large, Complex Data: Five New Directions in SAS/STAT Software." In it, Rodriguez summarizes five modern techniques for building predictive models and highlights recent SAS/STAT procedures that implement those techniques. The paper discusses the following high-performance (HP) […] The post Statistical model building and the SELECT procedures in SAS appeared first on The DO Loop.

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Do you write unnecessary SAS statements?

July 20, 2016
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Do you write unnecessary SAS statements?

I'm addicted to you. You're a hard habit to break. Such a hard habit to break. —  Chicago, "Hard Habit To Break" Habits are hard to break. For more than 20 years I've been putting semicolons at the end of programming statements in SAS, C/C++, and Java/Javascript. But lately I've been […] The post Do you write unnecessary SAS statements? appeared first on The DO Loop.

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