Blog Archives

Read sas7bdat files in R with GGASoftware Parso library

September 12, 2014
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... using the new R package sas7bdat.parso. The software company GGASoftware has extended the work of myself and others on the sas7bdat R package by developing a Java library called Parso, which also reads sas7bdat files. They have worked out most of the remaining kinks. For example, the Parso library reads sas7bdat files with compressed […]

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Making inferences about unusual population quantities.

April 5, 2014
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Making inferences about unusual population quantities.

This post builds on my last: Alternatives to model diagnostics for statistical inference?, where I had claimed that we could make quality inferences about the best linear approximation to a quadratic relationship. The R code below implements such a scenario, to establish a framework for discussion. I have inserted comments to augment the code. set.seed(42) […]

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Alternatives to model diagnostics for statistical inference?

March 28, 2014
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Alternatives to model diagnostics for statistical inference?

Consider the problem of making statistical inferences, as opposed to predictions. The product of statistical inference is a probabilistic statement about a population quantity, for example a 100(1-)% confidence interval for a population median. In this context, the principal reason for diagnostics is to comfort ourselves about the quality of such inferences. For example, we […]

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Image CGI with R

March 24, 2014
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I received an email recently with a question about using R in the common gateway interface (CGI) framework to create and pass image data to the web browser. I posted to stackoverflow about this some time ago, but had forgotten the details. The trouble is that R's graphics devices only write image data to file, […]

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A Recipe for Trellis/Faceted Plots Using Base R Graphics

July 6, 2013
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A Recipe for Trellis/Faceted Plots Using Base R Graphics

I frequently use lattice and ggplot2 to create trellis/faceted graphics. But, I gave up using these packages in a recent application, where I had initially constructed a complex graphic using the base R plotting functions. When I later decided that I wanted a faceted version, there was a dilema: re-create the complex graphic using lattice […]

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Descending Text in Righthand Margin of R Graphics à la mtext

June 29, 2013
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Descending Text in Righthand Margin of R Graphics à la mtext

There was an R-help thread in January regarding text in the righthand margin of an R graphic, where the text should be rendered in reading order from top to bottom. The base R function mtext is used to plot text in the margin. But, mtext is only able to render text from left to right […]

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Individual vs. Group Incentive for Weight Loss

April 11, 2013
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A new Annals of Internal Medicine article describes a study that compares two employer-sponsored financial incentive programs for promoting weight loss among obese employees. I first read about the article at the Pacific Standard. The study design is a randomized controlled prospective trial. The two programs are as follows: Program 1. Obese employees are given […]

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Generalized Pairs Plot: It’s about time!

March 28, 2013
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Generalized Pairs Plot: It’s about time!

JW Emerson, WA Green, B Schloerke, J Crowley, D Cook, H Hofmann, H Wickham (2013) The Generalized Pairs Plot. Journal of Computational and Graphical Statistics 22(1). Here's a free preprint version. Until this new paper and implementation by Emerson et al., there were no widely available pairs plots that accommodated both numerical and categorical fields. […]

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Simulated Power/Precision Analysis

February 22, 2013
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Simulated Power/Precision Analysis

I cringe when I see research proposals that describe a sophisticated statistical approach, yet do not evaluate this approach in their power/precision/sample size planning. It's often the case that a simplified version of the proposed statistical approach is used instead. Presumably, this is due to the limited availability of power/precision/sample size planning software for sophisticated […]

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My fiscal cliff letter to congress

December 6, 2012
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The ASA recently sent out an email asking its members to contact their representatives in congress to urge them to avoid the 8.2% cuts to NIH, NSF, and federal statistical agencies. I had been meaning to do this, but felt that the ASA letter template was too long. Here is the edited version that I […]

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