Publications by Wingfeet
Guns are cool
Reddit has a subreddit Guns are cool which in turn contains the MASS SHOOTINGS IN 2013 page. I pulled those data to see if there was anything of interest to plot or examine. I ended with modelling the frequency of shootings (once a day, Poisson distribution), and number of victims per shootings, a mixture of distributions, 2% of s...
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Mixed Models: Influence in Heterogeneous Variance Model
In this post I extend my knowledge of mixed models by redoing section 59.7 (page 5048) of the SAS/STAT user guide. I don’t think this particular example can be run in lme4, so that leaves nlme and MCMCglmm. MCMCglmm has less ability for influence measures, so this is only touched upon.dataTo quote the SAS/STAT User guide: ‘a one-w...
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Influence Analysis for Repeated Measures Data
I am trying exercise 59.8 (page 5057) of the SAS/STAT Users Guide 12.3 in R. The interesting thing is that influence is investigated on subject level rather than individual level. The diagnostics in nlme does not do leave-subject-out, at least, not that I know of. MCMCglm hardly has any diagnostics. This does not mean no validation is...
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Prices of houses in the Netherlands
The last couple of days I read a number of times about stabilization in house prices which had been dropping due to the crisis. And you get hit by numbers such as change against Q2 2013 or Q3 2012. These are accompanied by reasons why this or that quarter may be special so changes may be off. To be honest, after years of crisis I for ...
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Carry-over balanced designs for 8 treatments
Those are Williams designs you might say, but it has become clear to me that Williams designs are just a subset of all carry-over balanced designs. Not through hard work of mine, comments by Apn on my previous post Creating Williams designs with even number of products lead to this. Among other things, Apn claimed there were designs...
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Symmetry in Williams designs
Based on some comments I am looking at using symmetry to obtain Williams style designs. Symmetry allows reduction of the number of combinations examined hence faster calculation times. Two avenues are examined. Both work for a low number of treatments. For eight treatments they give different sets, which together define all 12 possibl...
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Statistical aspects of two-way cross-over studies
I ran into this presentation on Statistical aspects of two-way cross-over studies by Ing. Helmut Schütz (http://bebac.at). He presented some code and referred to the bear package. The bear package is menu driven, which is not my thing. I had to try and do that in R via other packages. The aim is to estimate if the treatments are bi...
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A small comparison of bio-equivalence calculations.
Last week I looked at two-way cross-over studies and followed the example of Schütz (http://bebac.at/) in the analysis. Since the EU has its on opinions (Questions & Answers: Positions on specific questions addressed to the pharmacokinetics working party) and two example data sets, I was wondering how the various computations compared.DataThere ...
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Dutch Rainwater Composition 1992-2005.
After reading Blog About Stats’ Open Data Index Blog Post I decided to browse a bit in the Open Data Index. Choosing Netherlands and following Emission of Pollutants I ended on a page from National Institute for Public Health. The page http://www.lml.rivm.nl/data/gevalideerd/index.html is in Dutch and chose composition of rain w...
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Dutch Rainwater Composition 1992-2011
Last week I examined rainwater composition 1992 to 2005. There is additional data, but National Institute for Public Health has changed equipment in 2005. This week I will add those data.DataData is in a number of spreadsheets. The script is a variation on last week, with an extra wrapper for spreadsheets. The final parts are merging locations...
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