Monitoring Price Fluctuations of Book Trade-In Values on Amazon

I am planning to finish school soon and I would like to shed some weight before moving on. I have collected a fair number of books that I will likely never use again and it would be nice to get some money for them. Sites like Amazon and eBay let you sell your book to other customers, but Amazon will also buy some of your books directly (Trade-Ins), saving you the hassle of waiting for a buyer.

Yet Another Baseball Defense Statistic

Fangraphs recently published an interesting dataset that measures defensive efficiency of fielders. For each player, the Inside Edge dataset breaks their opportunities to make plays into five categories, ranging from almost impossible to routine. It also records the proportion of times that the player successfully made the play. With this data, we can see how successful each player is for each type of play. I wanted to think of a way to combine these five proportions into one fielding metric.

Hastie and Tibshirani Interview Jerome Friedman

Trevor Hastie and Rob Tibshirani are currently teaching a MOOC covering an introduction to statistical learning. I am very familiar with most of the material in the course, having read Elements of Statistical Learning many times over. One great thing about the class, however, is that they are truely experts and have collaborated with many of the influencial researchers in their field. Because of this, when covering certain topics, they have included interviews with statisticians who made important developments to the field.

Top Songs by Artist on CD102.5 in 2013

In a previous post, I showed you how to scrape playlist data from Columbus, OH alternative rock station CD102.5. Since it's the end of the year and best-of lists are all the fad, I thought I would share the most popular songs and artists of the year, according to this data. In addition to this, I am going to make an interactive graph using Shiny, where the user can select an artist and it will graph the most popular songs from that artist.

Downloading and Analyzing CD1025's Playlist

CD1025 is an “alternative” radio station here in Columbus. They are one of the few remaining radio stations that are independently owned and they take great pride in it. For data nerds like me, they also put a real time list of recently played songs on their website. The page has the most recent 50 songs played, but you can also click on “Older Tracks” to go back in time.

Copying Data from Excel to R and Back

A lot of times we are given a data set in Excel format and we want to run a quick analysis using R's functionality to look at advanced statistics or make better visualizations. There are packages for importing/exporting data from/to Excel, but I have found them to be hard to work with or only work with old versions of Excel (*.xls, not *.xlsx). So for a one time analysis, I usually save the file as a csv and import it into R.

The Magical Sparse Matrix

I have been toying around with Kaggle's Million Song Dataset Challenge recently because I have some interest in collaborative filtering (using matrix factorization). I haven't made much progress with the competition (all 3 of my submissions are below the baseline), but I have learned a few things about dealing with large amounts of data. The goal of the competition is to predict the 500 most likely songs each of 110,000 users will listen to next.