# 2130 search results for "regression"

## Sales forecasting and direct mail optimization with Revolution R Enterprise and Alteryx

February 17, 2014
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If you missed our recent webinar Creating Value that Scales, you missed out on a live demonstration of the big-data analytics of Revolution R Enterprise embedded in the drag-and-drop visual workflow interface of Alteryx. If you want to see how a decision-maker can use the results of workflows created by data scientists, skip ahead to 25:45 to see a...

## Adjusting Chinese New Year Effects in R is Easy

February 17, 2014
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The Spring Festival is the most important holiday in China and many other Asian countries. Traditionally, the holiday starts on Chinese New Year’s Eve, and lasts to the Lantern Festival on the 15th day of the first month of the lunisolar calendar. The Chinese New Year is celebrated either in January or in February of

## Reproducible research, training wheels, and knitr

February 15, 2014
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$Reproducible research, training wheels, and knitr$

Last week I gave a short talk at CMU’s statistical computing seminar, Stat Bytes. I summarized why reproducible research (RR) and literate programming are worthwhile, not just for serious research but also for homework reports or statistical blog posts. I … Continue reading →

## ggplot Fit Line and Lattice Fit Line in R

February 13, 2014
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Let's add a fit line to a scatterplot!Fit Line in Base GraphicsHere's how to do it in base graphics:ols <- lm(Temp ~ Solar.R, data = airquality)summary(ols)plot(Temp ~ Solar.R, data = airquality)abline(ols)Fit line in base graphics in RFit Line in...

## Unit Root Tests

February 12, 2014
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$(Y_t)$

This week, in the MAT8181 Time Series course, we’ve discussed unit root tests. According to Wold’s theorem, if is  (weakly) stationnary then where is the innovation process, and where  is some deterministic series (just to get a result as general as possible). Observe that as discussed in a previous post. To go one step further, there is also the...

## Three ways to get parameter-specific p-values from lmer

February 11, 2014
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How to get parameter-specific p-values is one of the most commonly asked questions about multilevel regression. The key issue is that the degrees of freedom are not trivial to compute for multilevel regression. Various detailed discussions can be found on the R-wiki and R-help mailing list post by Doug Bates. I...

## Unprincipled Component Analysis

February 10, 2014
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As a data scientist I have seen variations of principal component analysis and factor analysis so often blindly misapplied and abused that I have come to think of the technique as unprincipled component analysis. PCA is a good technique often used to reduce sensitivity to overfitting. But this stated design intent leads many to (falsely) Related posts:

## After 1st semester of Statistics PhD program

February 9, 2014
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Have you ever wondered whether the first semester of a PhD is really all that busy? My complete lack of posts last fall should prove it Some thoughts on the Fall term, now that Spring is well under way: The … Continue reading →

## N2 with runlm()

February 9, 2014
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Introduction The default swN2() calculation in Oce uses a smoothing spline. One disadvantage of this is that few readers will know how it works. A possible alternative is to compute d(rho)/dz using the slope inferred from a running-window linear regression. Such a slope is provided by the new Oce function runlm(), which is tested here. (Note...

## Another skewed normal distribution

February 8, 2014
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$Another skewed normal distribution$

At the CLRS last year, Glenn Meyers talked about something very near to my heart: a skewed normal distribution. In loss reserving (and I'm sure, many other contexts) standard linear regression is less than ideal as it presumes that deviations from the mean are equally distributed. We rarely expect this assumption to hold (though we