Blog Archives

A Call for Contributors

October 29, 2013
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Dear Readers,This blog has been going for a year and a half now and I have posted nearly 300 posts to date.  I plan to continue to post though I am going to probably continue to shift my focus from daily blogging to that of getting a dissertation ...

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Modified Bin and Union Method for Item Pool Design

October 28, 2013
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Modified Bin and Union Method for Item Pool Design

# Reckase (2003) proposes a method for designing an item pool for a computer# adaptive test that has been known as the bin and union method. This method# involves drawing a subject from a distribution of abilities. Then selecting# the item that maximi...

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Maximum Likelihood Estimation and the Origin of Life

September 8, 2013
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Maximum Likelihood Estimation and the Origin of Life

# Maximum likelihood Estimation (MLE) is a powerful tool in econometrics which allows for the consistent and asymptotically efficient estimation of parameters given a correct identification (in terms of distribution) of the random variable. # It i...

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ThinkNum – A new interactive public database and graphing tool!

September 5, 2013
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ThinkNum – A new interactive public database and graphing tool!

Thinknum.com is a new free data service similar to Quandl.com in that they organize and list publicly available data sets.  Currently they are using data from 2,000 data sources which sounds good compared with Quandl's 400+ source.  Overall, ...

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Making regex examples work for you!

August 30, 2013
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One of the most frequently used string recognition algorithms out there is regex and R implements regex.  However, users can often be frustrated with how despite taking examples verbatim from many sources such as stackoverflow they do not seem to ...

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Doodling in R!

August 21, 2013
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Doodling in R!

# I am working on creating some functions that will be capable of creating shapes and plots that look hand drawn. # I have made some progress in this goal. # In that process I have also discovered that I can make some doodles that look hand d...

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Export R Results Tables to Excel – Please don’t kick me out of your club

August 19, 2013
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Export R Results Tables to Excel – Please don’t kick me out of your club

This post is written as a result of finding the following exchange on one of the R mailing lists:Is-there-a-way-to-export-regression-output-to-an-excel-spreadsheetQuestion: Is there a way to export regression output to an excel spreadsheet?Translation:...

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Question and Answer: Generating Binary and Discrete Response Data

August 19, 2013
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I was recently contacted by a reader with two very specific questions and I thought that this would be a good topic to publicity respond to. He would like to simulate his data:I have firm level data and the model is discrete choice with the main expla...

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A Stata HTML syntax highlighter in R

August 12, 2013
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So I have been having difficulty getting my Stata code to look the way I want it to look when I post it to my blog.  To alleviate this condition I have written a html encoder in R.  I don't know much about html so it is likely to be a little ...

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Item Equating with same Group – SAT, ACT example

August 5, 2013
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Item Equating with same Group – SAT, ACT example

# Item equating is the practice of making the results from two # different assessments equivalent. This can be done by either# 1. having the same group take both assessments# 2. having equivalent groups take the different assessments# 3. having non-eq...

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