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Assessing the fit of a count regression model is not necessarily a straightforward enterprise; often we just look at residuals, which invariably contain patterns of some form due to the discrete nature of the observations, or we plot observed versus fitted values as a scatter plot. Recently, while perusing the ... [Read more...]

Several years ago our team began using SurveyGizmo for our online surveys (and, actually, a bunch of other projects as well, from polls to data entry templates). At the time, SurveyGizmo provided a nice balance between cost and customization when compared to similar products from, e.g., Qualtrics and SurveyMonkey. ... [Read more...]

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Welcome to Introduction to R for Data Science Session 6: Linear Regression + EDA, and Normality tests [Linear Regression in R: Exploratory Data Analysis, assumptions of the simple linear model, correlation, and visualization. Predictions from the linear model. Confidence Intervals and Residuals. Inspecting the basic linear model. Infulential cases and the Influence ... [Read more...]

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Several years ago our team began using SurveyGizmo for our online surveys (and, actually, a bunch of other projects as well, from polls to data entry templates). At the time, SurveyGizmo provided a nice balance between cost and customization when compared to similar products from, e.g., Qualtrics and SurveyMonkey. ... [Read more...]

Time series analysis using max and min to describe brain signal data (event related potential). [Read more...]

Time series analysis using max and min to describe brain signal data (event related potential). [Read more...]

Introduction Time series has maximum and minimum points as general patterns. Sometimes the noise present on it causes problems to spot general behavior. In this post, we will smooth time series -reducing noise- to maximize the story that data has to tell us. And then, an easy formula will be ... [Read more...]

Ross Ihaka, one of the co-creators of R (along with Robert Gentleman), recently gave an interview to the University of Auckland's alumni magazine, Ingenio. In the article, he shares the story of the genesis of R in the early 1990s: The story all began back in the early 1990s when ... [Read more...]

[social4i size=”large” align=”float-right”] Guest post by Khushbu Shah The most common question asked by prospective data scientists is – “What [Read more...]

XGBoost is a fantastic open source implementation of Gradient Boosting Machines, a general purpose supervised learning method... [Read more...]

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Today’s post is by Kyle Walker, a professor of geography at Texas Christian University. I’ve been a fan of Kyle’s work for a while. When I saw that he wrote a package for accessing the Census Bureau’s International Data Base, I asked him to write a ... [Read more...]

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There are two ways to write error-free programs; only the third one works. – Alan Perlis Error messages can be intimidating for novice coders, and sometimes even for the experienced ones. Trying to decipher the error can be a time-consuming task. In this issue we look at some of the common ... [Read more...]

Six months ago we’ve introduced ‘The Proton’ – a console based R game with six data wrangling puzzles. Around 15-30 minutes of fun with data. The game is on CRAN in the package BetaBit. And just few days ago we’ve added a second game – frequon(). Eight puzzles related with ... [Read more...]