# 1881 search results for "time series"

## PK calculations for infusion at constant rate

March 16, 2014
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In this third PK posting I move to chapter 10, study problem 4 of Rowland and Tozer (Clinical pharmacokinetics and pharmacodynamics, 4th edition). In this problem one subject gets a 24 hours continuous dose. In many respects the Jags calculation is not very different from before, but the relation between parameters in the model and PK parameters is a...

## Testing for trend in ARIMA models

March 12, 2014
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Today’s email brought this one: I was wondering if I could get your opinion on a particular problem that I have run into during the reviewing process of an article. Basically, I have an analysis where I am looking at a couple of time-series and I wanted to know if, over time there was an upward trend in the...

## How effective is my research programming workflow? The Philip Test – Part 1

March 10, 2014
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Philip Guo, who writes a wonderful blog on his views and experiences of academia – including a lot of interesting programming stuff – came up with a research programming version of The Joel Test last summer, and since then I’ve been thinking of writing a series commenting on how well I fulfil each of the items on

## Guidebook for growth curve analysis

March 3, 2014
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I don't usually like to use complex statistical methods, but every once in a while I encounter a method that is so useful that I can't avoid using it. Around the time I started doing eye-tracking research (as a post-doc with Jim Magnuson), people were ...

March 1, 2014
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OECD.Stat is a commonly used statistics portal in the research world but there are no easy ways (that I know of) to query it straight from R. There are two main benefits of querying OECD.Stat straight from R: 1. Create reproducible analysis (something that is easily lost if you have to download excel files) 2.

## Bayes factor t tests, part 2: Two-sample tests

February 23, 2014
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In the previous post, I introduced the logic of Bayes factors for one-sample designs by means of a simple example. In this post, I will give more detail about the models and assumptions used by the BayesFactor package, and also how to do simple analyses of two- sample designs.See the previous posts for background: What is a...

## Because it’s Friday: US Dialects

February 21, 2014
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In the video below from The Atlantic, the differences in the way US citizens describe or pronounce various things is illustrated in a series of phone calls (via Sullivan): If you're wondering how your dialect fits in, you can try the New York Times Dialect Quiz. Answer 25 questions, and it will identify the 3 US cities that most...

February 20, 2014
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I shot a quick post over at the Data Driven Security blog explaining how to separate Twitter data gathering from R code via the Ruby t (github repo) command. Using t frees R code from having to be a Twitter processor and lets the analyst focus on analysis and visualization, plus you can use t

## Books and lessons about ggplot2

February 19, 2014
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I recently got an email from a person at Packt publishing, who suggested I write a book for them about ggplot2. My answer, which is perfectly true, is that I don’t have the time, nor the expertise to do that. What I didn’t say is that 1) a quick web search suggests that Packt doesn’t