I'm back from vacation, so I'll post something substantive later today.

I'm back from vacation, so I'll post something substantive later today.

I'm back from vacation, so I'll post something substantive later today.

A colleague of mine recently asked about computing basic summary statistics from grouped data in R. These are a couple examples that I suggested. Additional documentation for the plyr package can be found here. read more

The plot in section 7.3 has some problems. At the very least, the jittered values ought to be between 0 and 1, so the smoothed lines ﬁt better with them. Once again we use the data generated in section 7.2 as an example. For both SAS and R, we use conditioning (section 1.11.2) to make the jitter happen...

There's no doubt that by now you've noticed that we're big fans of R around here. It's completely free, has superior graphing capabilities, and with all the extension packages available there isn't much it can't do. One of the problems with R especially to new users is that it isn't obvious how to find help when you...

Just a short note that version 2.9.1 of R was released yesterday. And a corresponding Debian release went out as usual on the same day. One sour note: as the Java toolchain is currently broken, I had to disable compile-time support for Java. Just run R...

Just a short note that version 2.9.1 of R was released yesterday. And a corresponding Debian release went out as usual on the same day. One sour note: as the Java toolchain is currently broken, I had to disable compile-time support for Java. Just run R CMD javareconf once installed if you need it. Speaking of broken, I had...

Our article (by Yu-Sung, Jennifer, Masanao, and myself, and based also on work with Kobi, Grazia, and Peter Messeri) will be appearing in the Journal of Statistical Software, in a special issue on missing-data imputation. Here's the abstract: ...

Something that's very important to be able to do in data analysis and visualization is to filter out cases. Let's say you want to do identical analyses of two different groups, or of one group and then a subset of it. R can do this a little differently; instead of merely filtering out cases you can create an object...

Development of the R package tikzDevice has been underway for about a month now. This package allows for the output of R graphics as TikZ commands. Charlie Sharpsteen and I have gotten it into an alpha stage. There is no real documentation but there is plenty of comments in the code. We have a R-forge

Before we delve into slightly more advanced plotting commands I want to talk a little about linear models, specifically, linear regression. In R this is very, very simple. For instance, in our 'states' data frame, we might want to look at median household income as a predictor of state education expenditures. The command lm calculates this for us. We'll...

Before we delve into slightly more advanced plotting commands I want to talk a little about linear models, specifically, linear regression. In R this is very, very simple. For instance, in our 'states' data frame, we might want to look at median household income as a predictor of state education expenditures. The command lm calculates this for us. We'll...

Using Microsoft Excel I'm collecting aggregate data, by state, of various social, political, and economic indicators. I export them into a tab-delimited file called 'states.txt' (pretty clever, I know.) I've got data on education expenditures, firearm deaths per capita, median household income, etc. I'd like to do some analysis and graphing of these data to see if there are...

In R, the way to delete a component in a list object is different from matrix and vector objects. For a vector, to delete an element:vec <- c(1, 2, 3)vec <- vecFor a matrix, to delete a row or a column:mat <- matrix(c(1,2,3,4), 2, 2)mat2 <- mat # delete a rowmat3 <- mat # delete a columnFor a list,...