Blog Archives

Mixed models; Random Coefficients, part 1

September 8, 2013
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Mixed models; Random Coefficients, part 1

Continuing with my exploration of mixed models I am now at the first part of random coefficients: example 59.5 for proc mixed (page 5034 of the SAS/STAT 12.3 Manual). This means I skipped examples 59.3 (plotting the likelihood) and 59.4 (known G and R)...

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Mixed models exercise 2. Repeated measurements

September 1, 2013
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Continuing my exploration of mixed models, I now understand what is happening in the second SAS(R)/STAT example for proc mixed (page 5007 of the SAS/STAT 12.3 Manual). It is all about correlation between the time-points within subjects. The data as suc...

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More REML exercise

August 25, 2013
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Last week I tried exercise 1 of the SAS(R) proc mixed with R libraries lme4 and MCMCglm. So this week I aimed for exercise 2 but ended up redoing exercise 1 with nlme.Exercise 2 results gave me problems with library lme4 and latter parts of the ex...

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Exercise in REML/Mixed model

August 18, 2013
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I want to build a bit more experience in REML, so I decided to redo some of the SAS examples in R. This post describes the results of example 59.1 (page 5001, SAS(R)/STAT User guide 12.3 link). Following the list from freshbiostats I will analyze ...

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More rainfall calculations – REML

August 4, 2013
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More rainfall calculations – REML

I wanted to have a look at various REML methods for a long time. The rainfall data seemed a nice example. On top of that, FreshBiostats had a blog post 'Mixed Models in R: lme4, nlme, or both?'. So lme4 it is.The data  As described before; th...

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A JAGS calculation on pattern of rain January 1906-1915 against 2003-2012

July 28, 2013
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Two weeks ago I showed rain data from six stations in Netherlands years 1906 till now. Last week I showed that frequency of days with and without rain differed between December 1906-1915 and December 2003-2012. This week I am considering the ...

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Did the pattern of rain change in the last 100 years?

July 21, 2013
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Did the pattern of rain change in the last 100 years?

Last week I showed rain data from six stations in Netherlands years 1906 till now. The obvious next question is; did it change? A surprisingly difficult question. The data is not normal distributed, but it is time-correlated, location correlated.T...

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Rain in Netherlands during the past 100 years

July 14, 2013
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Rain in Netherlands during the past 100 years

Climate has my interest. But discussions on climate change seem to be focused on temperature. In real life, we look at temperature, rain, sunshine and wind. I was therefor happy to find a load of rain data on Royal Netherlands Meteorological Institute....

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change in weight of cars plot

July 7, 2013
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change in weight of cars plot

Based on last week's faster algorithm I wanted to finish with car weights. Unfortunately a fail again. By now it is a fail of myself, it needs a bit more dedication and grunt than I am willing and able to give for this blog. This week I added...

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Faster calculation

June 30, 2013
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Last week I decided to speed up my distribution fitting functions of two weeks ago. These were bold words. My try of Rcpp was a failure. Just plain optimization helped a bit better. Using the compiler package added a bit. (the compiler package does not...

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