This post is about ggplot2 and dplyr packages, so let’s start with loading them: library(ggplot2) library(dplyr) I can’t be the first person to make the following mistake: ggplot(mtcars, aes(x = wt, y = mpg)) %>% geom_point() Can you spot the mistake in the code above? Look closely at the end of the first line. The operator should be the + used in ggplot2 for layering, not the %>% operator used in dplyr for piping, like this:
The other day on the isostat mailing list Doug Andrews asked the following question: Which R packages do you consider the most helpful and essential for undergrad stat ed? I ask in great part because it would help my local IT guru set up the way our network makes software available in our computer classrooms, but also just from curiosity. Doug asked for a top 10 list, and a few people have already chimed in with great suggestions.
Somehow almost an entire academic year went by without a blog post, I must have been busy… It’s time to get back in the saddle! (I’m using the classical definition of this idiom here, “doing something you stopped doing for a period of time”, not the urban dictionary definition, “when you are back to doing what you do best”, as I really don’t think writing blog posts are what I do best…)
I have gotten several requests for the R syntax I used to analyze the ranked-choice voting data and create the animated GIF. Rather than just posting the syntax, I thought I might write a detailed post describing the process. Reading in the Data The data is available on the Twin Cities R User Group’s GitHub page. The file we are interested in is 2013-mayor-cvr.csv. Clicking this link gets you the “Display” version of the data.
Daniel Kaplan and Libby Shoop have developed a one-credit class called Data Computation Fundamentals, which was offered this semester at Macalester College. This course is part of a larger research and teaching effort funded by Howard Hughes Medical Institute (HHMI) to help students understand the fundamentals and structures of data, especially big data. [Read more about the project in Macalester Magazine.] The course introduces students to R and covers topics such as merging data sources, data formatting and cleaning, clustering and text mining.
We have just finished another semester, and before my mind completely turns to rubble, I want to share what I believe to be a fairly good assignment. What I present below was parts of two separate assignments that I gave this semester, but upon reflection I think it would be better as one. Read the article Let’s Practice What We Preach: Turning Tables into Graphs (full reference given below). In this article, Gelman, Pascarica, & Dodhia suggest that presentations of results using graphs are more effective than results presented in tables.
I have been thinking for quite some time about the computing skills that graduate students will need as they exit our program. It is absolutely clear to me (not necessarily all of my colleagues) that students need computing skills. First, a little background… I teach in the Quantitative Methods in Education program within the Educational Psychology Department at the University of Minnesota. After graduating, many of our students take either academic jobs, a job working in testing companies (e.