# Monthly Archives: April 2010

## Estimating Missing Data with aregImpute() {R}

April 19, 2010
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Missing Data Soil scientists routinely sample, characterize, and summarize patterns in soil properties in space, with depth, and through time. Invariably, some samples will be lost or sufficient funds required for complete characterization can run out. In these cases the scientist is left with a data table that contains holes (so to speak) in the rows/columns that are...

## R tip: Maximum screen width

April 19, 2010
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R can be annoying in that even if you stretch your terminal or R GUI session to a whole screen width it will still only show 80 characters width. This can make wide tables really hard to read. options(width=150)Use the options command width to set...

## Example 7.33: Specifying fonts in graphics

April 19, 2010
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For interactive data analysis, the default fonts used by SAS and R are acceptable, if not beautiful. However, for publication, it may be important to manipulate the fonts. For example, it would be desirable for the fonts in legends, axis labels, or o...

## Getting your web application and R(Apache) to talk to each other

April 19, 2010
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Here’s the situation. Web applications, built using a framework (e.g. Rails, Django) are great for fetching data from a database and rendering it. They’re not so great for crunching and charting the data. Conversely, R is great for crunching and charting, but doesn’t make for a great web application. The idea then, is to let

## Thoughts on LSPM from R/Finance 2010

April 18, 2010
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I just got back from R/Finance 2010 in Chicago. If you couldn't make it this year, I strongly encourage you to attend next year. I will post a more comprehensive review of the event in the next couple days, but I wanted to share some of my notes spec...

## Sudokus more random than random!

April 18, 2010
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$Sudokus more random than random!$

Darren Wraith pointed out this column about sudokus to me. It analyses the paper by Newton and De Salvo published in the Proceedings of the Royal Academy of Sciences A that I cannot access from home. The discussion contains this absurd sentence “Sudoku matrices are actually more random than randomly-generated matrices” which shows how mistreated

## Summarising data using scatter plots

April 18, 2010
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A scatter plot is a graph used to investigate the relationship between two variables in a data set. The x and y axes are used for the values of the two variables and a symbol on the graph represents the combination for each pair of values in the data set. This type of graph is

## alphahull: an R Package for Alpha-Convex Hull

April 16, 2010
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new paper on the α-convex hull appeared in the Journal of Statistical Software today (http://www.jstatsoft.org/v34/i05/paper). The α-convex hull is an interesting problem which caught my attention long time ago but I didn’t know a solution then. R has a function chull() which can generate (indices of) the convex hull for a series of points. Now

## Significant Figures in R and Rounding

April 16, 2010
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This is a follow-on to my previous post about determining significant digits, or sigdigs, in performance and capacity planning calculations. Once we know how to do that, inevitably we will be faced with rounding the result of a calculation to the least...

## Simulating Dart Throws in R

April 16, 2010
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Back in November 2009 Wired wrote an article about some grad students who decided to try to stochastically model throwing darts. Because I don’t actually read printed material I didn’t see the article until a couple of months ago. My immediate thought was, “hey, I drink beer. I throw darts. I build stochastic models. Why