Monthly Archives: March 2011

IV Regression

March 8, 2011
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IV Regression

Here is my code from a previous post that performs IV regression. This may be easier to copy into an R script. I will post a video tutorial using this code shortly.

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Machine Learning Ex3 – multivariate linear regression

March 8, 2011
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Machine Learning Ex3 – multivariate linear regression

Exercise 3 is about multivariate linear regression. First part is about finding a good learning rate (alpha) and 2nd part is about implementing linear regression using normal equations instead of the gradient descent algorithm.DataAs usual hosted in google docs:mydata = read.csv("http://spreadsheets.google.com/pub?key=0AnypY27pPCJydExfUzdtVXZuUWphM19vdVBidnFFSWc&output=csv", header = TRUE)# show last 5 rows tail(mydata, 5)area bedrooms price 43 2567 ...

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An enhanced Kaplan-Meier plot

March 8, 2011
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An enhanced Kaplan-Meier plot

We often see, in publications, a Kaplan-Meier survival plot, with a table of the number of subjects at risk at different time points aligned below the figure. I needed this type of plot (or really, matrices of such plots) for an upcoming publication. Of course, my preferred toolbox was R and the ggplot2 package. There

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Our Friend the Age-Earnings Profile

March 7, 2011
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Our Friend the Age-Earnings Profile

I like Labor Economics. Partially because it has a nice mix of theory and practical empiricism, but mostly because it seems to be a sub-field with a number of agreed upon stylized facts that grow not out of micro theory … Continue reading →

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Initial SoilWeb Concept on Paper

March 7, 2011
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Initial SoilWeb Concept on Paper

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money is coin $ flip

March 7, 2011
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money is coin $ flip

Well, sorta. More precisely, money is the sum of coin$flip divided by the number of coin$flip. But we'll get to that later. For now, let me introduce you to a new algorithm written in R. This one is another "quote" -- simple few lines of code -- whose ...

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Alabama is a foreign country

March 7, 2011
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Alabama is a foreign country

Faculty and students of Iowa State University Department of Statistics published online an analysis of the data on 2009 distributions of the US Stimulus funds, aka the Recovery And Reinvestment Act. (The analysis was published in March last year as part of the Design for America competition, but I only recently came across it.) The analyses and associated charts...

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Basic Plots in R

March 7, 2011
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Basic Plots in R

Here's a tutorial I recorded on producing basic plots in R.I lost the script file I used to create the video to a horrifying black screen of death, but I used the data from the previous post (available here). Hopefully, the video is clear enough that ...

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Visualizing the Language Used by Academics when Protected by Anonymity

March 7, 2011
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Those in the political science discipline probably remember their first encounter with poliscijobrumors.com. For those outside, you have probably never heard of this particular message board, and you would have no reason to. As the URL suggests, the board specializes in rumor, gossip, back-bitting, mudslinging, and the occasional lucid thread on the political science

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Example 8.29: Risk ratios and odds ratios

March 7, 2011
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Example 8.29: Risk ratios and odds ratios

When can you safely think of an odds ratio as being similar to a risk ratio?Many people find odds ratios hard to interpret, and thus would prefer to have risk ratios. In response to this, you can find several papers that purport to convert an odds rat...

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