Tag Archives: R

Stratified random sampling in R from a data frame

By Ananda | Published: May 20, 2011

After a little bit more work, there’s a new stratified random sampling function, this one letting you sample from a data frame, returning all the variables for each of your samples as a nice data frame that you can continue working on as usual. Get the function at http://news.mrdwab.com/stratified. Usage notes in the head of [...]

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Stratified Random Sampling in R–A Function in Progress

By Ananda | Published: May 15, 2011

IMPORTANT: This is here mostly to remind me of how I solved my problem. You should read Stratified random sampling in R from a data frame if you really want to use this function. I know that sampling is quite complex, and I will admit that I know very little about its complexities. Fortunately, software [...]

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Reshaping data in R revisited

By Ananda | Published: April 18, 2011

A year ago, I wrote a post about reshaping data from a wide format to a long format. I thought that considering how much time had passed, it would be good to revisit R’s in-built reshape functions. For these examples, I’ve copied the Stata examples from the UCLA Academic Technology Services’s “Reshape data wide to [...]

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Regular expressions in R

By Ananda | Published: March 8, 2011

In my last post (Sounds interesting. Is that a regular expression?), I showed a few things I had figured out recently related to regular expressions. By now, you have also figured out that I like figuring things out in R, and application of regular expressions is one of these things.

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Sounds interesting. Is that a regular expression?

By Ananda | Published: March 7, 2011

I’ve been meaning to learn how to use regular expressions for quite some time now, but just never seemed to get around to doing so. The other night, I decided to take a stab at them though, and over the past few days, I’ve sort of managed to learn a few tricks. Some of these [...]

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The new sample size calculator for R (already)

By Ananda | Published: September 10, 2010

aka “Maybe I shouldn’t post so quickly” Just hours ago, I posted my first set of functions for R to determine the sample size for a known population. Then, I had to update that post to reflect my newfound knowledge, and now, I thought I would update again, so that the best functions I came [...]

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A sample size calculator function for R

By Ananda | Published: September 10, 2010

IMPORTANT: This is here mostly to remind me of how I solved my problem. You should read The new sample size calculator for R (already) if you really want to use this function. In the research class at the Tata-Dhan Academy, students are currently getting into sampling, so I thought I would introduce them to [...]

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Using the reshape package in R for pivot-table-like functionality

By Ananda | Published: August 8, 2010

A little more than a week ago, I wrote about creating pivot tables in Microsoft Excel and OpenOffice.org. I also mentioned that I would explain how to do similar calculations by using R. This post will explain how to achieve similar results in R by using the reshape package. I had initially started experimenting with [...]

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Getting data into R

By Ananda | Published: July 11, 2010

When you first open R, you’re greeted with a screen similar to the following: ?View Code RSPLUS1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 R version 2.10.0 (2009-10-26) Copyright (C) 2009 The R Foundation for Statistical Computing ISBN 3-900051-07-0   R is free software [...]

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R is like a giant calculator for grownups

By Ananda | Published: June 30, 2010

One of the things that is interesting about R is how flexible it is. One of the fun things about it is how interactive it can be. While my examples so far have been a little bit more involved, it can be useful to spend some time just getting acquainted with how R performs basic [...]

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