This is it, the last question on the exam! 28. A telephone survey was conducted several years ago, asking people how often they were polled in the past year. I can’t recall the responses, but suppose that 40% of the respondents said they participated in zero surveys in the previous year, 30% said they participated [...]
This is update 4 to my original post about predicting the NBA playoffs with R. With the Thunder beating the Spurs and the Heat losing to the Celtics, the algorithm went 1-1 on predictions, making it 5-3 so far. Making some improvements I have been po...
This is update 4 to my original post about predicting the NBA playoffs with R. With the Thunder beating the Spurs and the Heat losing to the Celtics, the algorithm went 1-1 on predictions, making it 5-3 so far. Making Continue reading →
This is update 4 to my original post about predicting the NBA playoffs with R. With the Thunder beating the Spurs and the Heat losing to the Celtics, the algorithm went 1-1 on predictions, making it 5-3 so far. Making some improvements I have been pos...
Graph designers often try to put too much information in one plot resulting in confusing plots that are difficult to read. Trellis plots often provide the solution to displaying the data clearly.
Last Updated on Wednesday, 06 June 2012Published by Media Helping Media on Wednesday, 06 June 2012Written by Brian Boyer, John Keefe, Friedrich Lindenberg, Jane Park, Chrys WuGetting started in data journalismLooking for data on a particular topic or i...
Daniel Mendelsohn recently asked, “Why do we love the Titanic?”, seeking to understand how it has happened that: It may not be true that ‘the three most written-about subjects of all time are Jesus, the Civil War, and the Titanic,’ as one historian has put it, but it’s not much of an exaggeration. . . [...]
The following chart by the Financial Times reminds me of the famous Napoleon Russian Campaign map: I also love it when geographical data, in this case average house price data by region, are plotted without a map. If plotted on...
Recently I have stumbled on a problem with split function applied on list of factors. The issue is that it might produce wrong splits when splitting factors contain dots.Here is the example of the problem. Invoking the following code:df <-...
Day 2 of EuroVis was a long series of paper presentations, occasionally interrupted with copious amounts of food. Here are some of the highlights. The Parallel Coordinates Matrix by Julian Heinrich, John Stasko, and Daniel Weiskopf describes a way of arranging axes in parallel coordinates to show all two-axis combinations without (much) redundancy. Doing this, it is possible to find all the interesting patterns in data without having to try…
A few more comments on the specific entry on ABC written by Mikael Sunnåker et al…. The entry starts with the representation of the posterior probability of an hypothesis, rather than with the posterior density of a model parameter, which seems to lead the novice reader astray. After all, (a) ABC was not introduced for [...]
27. Which of the following problems were identified with the Burnham et al. survey of Iraq mortality? (Indicate all that apply.) (a) The survey used cluster sampling, which is inappropriate for estimating individual out- comes such as death. (b) In their report, Burnham et al. did not identify their primary sampling units. (c) The second-stage [...]
The Problem In the United States, people are getting fatter and they are doing so at an alarming rate. So What? Being fat isn't just a social stigma - it's unhealthy in nearly every facet of life. Staying in this condition brings hi...
In this post I show a simple illustration of a mixture of normal distributions. For the examples, we assume we have metric values that we suppose are generated by a mixture of two different normal distributions, which I'll call clusters. We don't know ...
Jay Livingston points to an excellent rant from Peter Moskos, trashing a study about “food deserts” (which I kept reading as “food desserts”) in inner-city neighborhoods. Here’s Moskos: From the Times: There is no relationship between the type of food being sold in a neighborhood and obesity among its children and adolescents. Within a couple [...]
Big data is getting a lot of buzz lately, but small data is interesting too. In some ways it’s more interesting. Because of limit theorems, a lot of things become dull in the large that are more interesting in the…Read more ›
"Help! My simulation is taking too long to run! How can I make it go faster?" I frequently talk with statistical programmers who claim that their "simulations are too slow" (by which they mean, "they take too long"). They suspect that their program is inefficient, but they aren't sure why. [...]
This post is from my new book Forecasting: principles and practice, available freely online at OTexts.com/fpp/. A non-seasonal ARIMA model can be written as (1) or equivalently as (2) where is the backshift operator, and is the mean of . R uses the parametrization of equation (2). Thus, the inclusion of a constant in a non-stationary ARIMA model is equivalent to inducing a polynomial trend of order in…
The little online shop Meshu [meshu.io] turns one's travel itineraries into wearable jewelry, such as a necklace, earrings, or cufflinks, custom made in either acrylic, wood, nylon, and silver One can either select a series of cities on a world map,...
EuroVis 2012 has officially begun, so here is a brief recap of some of the things I found interesting. Today, that included the EuroRVVV workshop and two papers. My goal with these postings, as with my tweeting, will not be to cover everything that happens, but very selectively describe things that were remarkable for whatever reason. EuroRVVV The workshop with the horrible name (Paul Rosenthal pronounces it “Euro-R-Triple-V”) turned out…
26. You have just graded an an exam with 28 questions and 15 students. You fit a logistic item- response model estimating ability, difficulty, and discrimination parameters. Which of the following statements are basically true? (Indicate all that apply.) (a) If a question is answered correctly by students with very low and very high ability, [...]
The Bland-Altman plot is a visual aid for assessing differences between two ways of measuring something. For example, one might compare two scales this way, or two devices for measuring particulate matter. The plot simply displays the difference betw...
This is my third update to my original post on predicting the NBA playoffs with an algorithm. Here are updates 1 and 2. The algorithm correctly predicted a Boston win, but missed on the Spurs/Thunder game, so it is currently 4-2. Haven’t had a...
