Global Fires, the Amazon and Humans

May 23, 2012
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Global Fires, the Amazon and Humans

Fires are natural - most of the time (click on image for larger view).Natural Global FiresMany plants and animals have evolved to depend on fires periodically occurring in certain parts of the world. This phenomenon has been occurring for millions of y...

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ThreadWatch: Tracking and Visualizing the Use of Software Applications

May 23, 2012
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ThreadWatch: Tracking and Visualizing the Use of Software Applications

ThreadWatch [finekost.com] by interactive developer Alex Milde visualizes the usage of software programs on the Mac platform over the timeframe of one day. First, one needs to download a small program that tracks all active applications on your desk...

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Advice on writing research articles

May 23, 2012
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From a few years ago: Both the papers sent to me appear to have strong research results. Now that the research has been done, I’d recommend rewriting both articles from scratch, using the following template: 1. Start with the conclusions. Write a couple pages on what you’ve found and what you recommend. In writing these [...]

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Hans Rosling: Religions and babies

May 23, 2012
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Hans Rosling: Religions and babies

Hans Rosling had a question: Do some religions have a higher birth rate than others -- and how does this affect global population growth? Speaking at the TEDxSummit in Doha, Qatar, he graphs data over time and across religions. With his trademark humor...

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Compute statistics for each row by using subscript operators

May 23, 2012
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Compute statistics for each row by using subscript operators

In a previous blog, I showed how to use SAS/IML subscript reduction operators to compute the location of the maximum values for each row of a matrix. The subscript reduction operators are useful for computing simple statistics for each row (or column) of a numerical matrix. If x is a [...]

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My On-Job Training Analytics

May 23, 2012
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My On-Job Training Analytics

I have been working at Provincial Statistics Office of Tawi-Tawi (Philippines) which was part of the training on my OJT (On-Job Training). One of the requirements of the training is at least 80 hours of services, so I decided to work from April 19 to M...

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My new forecasting textbook

My new forecasting textbook

After years of saying that I was going to write a book to replace Makridakis, Wheelwright and Hyndman (1998), I’m finally ready to make an announcement! My new book is Forecasting: principles and practice, co-authored with George Athanasopoulos. ...

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My new forecasting textbook

May 23, 2012
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My new forecasting textbook

After years of saying that I was going to write a book to replace Makridakis, Wheelwright and Hyndman (1998), I’m finally ready to make an announcement! My new book is Forecasting: principles and practice, co-authored with George Athanasopoulos. It is available online and free-of-charge. We have written about 2/3 of the book so far (all of which is already available online), and we plan to finish it by the end…

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Question 12 of my final exam for Design and Analysis of Sample Surveys

May 22, 2012
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Question 12 of my final exam for Design and Analysis of Sample Surveys

12. A researcher fits a regression model predicting some political behavior given predictors for demographics and several measures of economic ideology. The coefficients for the ideology measures are not statistically significant, and the researcher creates a new measure, adding up the ideology questions and creating a common score, and then fits a new regression including [...]

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The Voting Patterns of the Eurovision Song Contest in the last 10 Years

May 22, 2012
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The Voting Patterns of the Eurovision Song Contest in the last 10 Years

In less than a week, more than 125 million people will be watching the 2012 edition of the Eurovision Song Contest, the annual competition held among active member countries of the European Broadcasting Union (EBU). An important part of the televise...

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Battle of the Repo Man quotes: Reid Hastie’s turn

May 22, 2012
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In response to my comments on his recent opinion article on the the human tendency to overvalue information presented as stories, Reid Hastie writes: Andrew (and Commenters) … I’d like to try to clarify some of the statements and implications in my Bloomberg article on “Our Gift for Good Stories …” The essay is what [...]

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Significance

May 22, 2012
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Significance

In statistical analysis the word “significant” means that there is evidence that effect found in the sample exists in the population from which the sample was drawn. The choice of the word “significant” is unfortunate, as it is used to … Continue reading →

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Correlations and postive-definiteness

May 22, 2012
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Correlations and postive-definiteness

On the way to another destination, I found some curious behavior with average correlations. The data Daily log returns from almost all of the constituents of the S&P 500 for years 2006 through 2011. The behavior Figure 1 shows the actual mean correlation among stocks for the set of years and the mean correlation with … Continue reading →

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Two black eyes for science, what a shame

May 22, 2012
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Two cautionary tales appeared in press recently, serving notice to all "data scientists" (as statisticians are fancifully called these days). It's hard work to earn the status of a "science". Via the New York Times comes the story of Dr. Robert Spitzer (link). As a young psychiatrist in the 1970s, he successfully pushed the profession to narrow the definition of homosexuality as a disorder. He observed wrily that many gay…

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Classical Technical Patterns

May 22, 2012
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Classical Technical Patterns

In my presentation about Seasonality Analysis and Pattern Matching at the R/Finance conference, I used examples that I have previously covered in my blog: Month of the Year Seasonality – I introduced the Seasonality charts in the Historical Seasonality Analysis: What company in DOW 30 is likely to do well in January? post. I also [...]

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Hans Rosling’s Shortest Talk Ever

May 21, 2012
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Hans Rosling’s Shortest Talk Ever

One does not require flashy Powerpoint slides or state exact statistical numbers to be able to convey an educational yet compelling presentation. Nor should the presentation need to take that long. Hans Rosling, who is already known to use physical ...

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Question 11 of my final exam for Design and Analysis of Sample Surveys

May 21, 2012
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Question 11 of my final exam for Design and Analysis of Sample Surveys

11. Here is the result of fitting a logistic regression to Republican vote in the 1972 NES. Income is on a 1–5 scale. Approximately how much more likely is a person in income category 4 to vote Republican, compared to a person income category 2? Give an approximate estimate, standard error, and 95% interval. Solution [...]

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Example 9.32: Multiple testing simulation

May 21, 2012
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Example 9.32: Multiple testing simulation

In examples 9.30 and 9.31 we explored corrections for multiple testing and then extracting p-values adjusted by the Benjamini and Hochberg (or FDR) procedure. In this post we'll develop a simulation to explore the impact of "strong" and "weak" control...

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Checking the Normality Assumption for an ANOVA Model

May 21, 2012
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Checking the Normality Assumption for an ANOVA Model

The assumptions are exactly the same for ANOVA and regression models. The normality assumption is that residuals follow a normal distribution. You usually see it like this: ε~ i.i.d. N(0, σ²) But what it's really getting at is the distribution of Y|X.

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Responding to a bizarre anti-social-science screed

May 21, 2012
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Philosophy professor Gary Gutting writes: Public policy debates often involve appeals to results of work in social sciences like economics and sociology. . . . How much authority should we give to such work in our policy decisions? . . . The core natural sciences (e.g., physics, chemistry, biology) are so well established that we [...]

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Aspirational & Useful: deck.rb with RStudio/knitr & Go2Shell

May 21, 2012
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Aspirational & Useful: deck.rb with RStudio/knitr & Go2Shell

There has been some interest in the recent release of RStudio 0.96 and especially the ability to use combine its knitr Markdown functionality with Pandoc to integrate R and a variety of different documents types. I just wanted to add two quick things ...

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For each observation, find the variable that contains the minimum value

May 21, 2012
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For each observation, find the variable that contains the minimum value

The other day I encountered an article in the SAS Knowledge Base that shows how to write a macro that "returns the variable name that contains the maximum or minimum value across an observation." Some people might say that the macro is "clever." I say it is complicated. This is [...]

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