Posts Tagged ‘ Data Analysis ’

The difference between CLASS statements and BY statements in SAS

February 14, 2018
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The difference between CLASS statements and BY statements in SAS

When I first learned to program in SAS, I remember being confused about the difference between CLASS statements and BY statements. A novice SAS programmer recently asked when to use one instead of the other, so this article explains the difference between the CLASS statement and BY variables in SAS [...] The post The difference between CLASS statements and BY statements in SAS appeared first on The DO Loop.

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10 posts from 2017 that deserve a second look

January 10, 2018
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10 posts from 2017 that deserve a second look

Last week I wrote about the 10 most popular articles from The DO Loop in 2017. My most popular articles tend to be about elementary statistics or SAS programming tips. Less popular are the articles about advanced statistical and programming techniques. However, these technical articles fill an important niche. Not [...] The post 10 posts from 2017 that deserve a second look appeared first on The DO Loop.

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Label multiple regression lines in SAS

January 8, 2018
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Label multiple regression lines in SAS

A SAS programmer asked how to label multiple regression lines that are overlaid on a single scatter plot. Specifically, he asked to label the curves that are produced by using the REG statement with the GROUP= option in PROC SGPLOT. He wanted the labels to be the slope and intercept [...] The post Label multiple regression lines in SAS appeared first on The DO Loop.

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The top 10 posts from The DO Loop in 2017

January 3, 2018
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The top 10 posts from The DO Loop in 2017

I wrote more than 100 posts for The DO Loop blog in 2017. The most popular articles were about SAS programming tips, statistical data analysis, and simulation and bootstrap methods. Here are the most popular articles from 2017 in each category. General SAS programming techniques INTCK and INTNX: Do you [...] The post The top 10 posts from <em>The DO Loop</em> in 2017 appeared first on The DO Loop.

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How to create a sliced fit plot in SAS

December 20, 2017
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How to create a sliced fit plot in SAS

I previously showed an easy way to visualize a regression model that has several continuous explanatory variables: use the SLICEFIT option in the EFFECTPLOT statement in SAS to create a sliced fit plot. The EFFECTPLOT statement is directly supported by the syntax of the GENMOD, LOGISTIC, and ORTHOREG procedures in [...] The post How to create a sliced fit plot in SAS appeared first on The DO Loop.

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Visualize multivariate regression models by slicing continuous variables

December 18, 2017
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Visualize multivariate regression models by slicing continuous variables

Slice, slice, baby! You've got to slice, slice, baby! When you fit a regression model that has multiple explanatory variables, it is a challenge to effectively visualize the predicted values. This article describes how to visualize the regression model by slicing the explanatory variables. In SAS, you can use the [...] The post Visualize multivariate regression models by slicing continuous variables appeared first on The DO Loop.

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3 problems with mean imputation

December 6, 2017
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3 problems with mean imputation

In a previous article, I showed how to use SAS to perform mean imputation. However, there are three problems with using mean-imputed variables in statistical analyses: Mean imputation reduces the variance of the imputed variables. Mean imputation shrinks standard errors, which invalidates most hypothesis tests and the calculation of confidence [...] The post 3 problems with mean imputation appeared first on The DO Loop.

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Visualize patterns of missing values

November 29, 2017
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Visualize patterns of missing values

Missing values present challenges for the statistical analyst and data scientist. Many modeling techniques (such as regression) exclude observations that contain missing values, which can reduce the sample size and reduce the power of a statistical analysis. Before you try to deal with missing values in an analysis (for example, [...] The post Visualize patterns of missing values appeared first on The DO Loop.

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Should you use principal component regression?

October 25, 2017
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Should you use principal component regression?

This article describes the advantages and disadvantages of principal component regression (PCR). This article also presents alternative techniques to PCR. In a previous article, I showed how to compute a principal component regression in SAS. Recall that principal component regression is a technique for handling near collinearities among the regression [...] The post Should you use principal component regression? appeared first on The DO Loop.

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The diffogram and other graphs for multiple comparisons of means

October 18, 2017
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The diffogram and other graphs for multiple comparisons of means

In a previous article, I discussed the lines plot for multiple comparisons of means. Another graph that is frequently used for multiple comparisons is the diffogram, which indicates whether the pairwise differences between means of groups are statistically significant. This article discusses how to interpret a diffogram. Two related plots [...] The post The diffogram and other graphs for multiple comparisons of means appeared first on The DO Loop.

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