1415 search results for "regression"

Tidbit: Correlation and Simple Linear Regression

October 19, 2012
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In business "Correlation" is generically used as a mutual relationship or connection between two or more things; statistically speaking correlation is the interdependence of variable quantities. I overhear many end users request information on the correlation of variables for prediction use, what they are referring to is actually simple linear regression. I don't mean to outline all

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Example 10.6: Should Poisson regression ever be used? Negative binomial vs. Poisson regression

October 15, 2012
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Example 10.6: Should Poisson regression ever be used? Negative binomial vs. Poisson regression

In practice, we often find that count data is not well modeled by Poisson regression, though Poisson models are often presented as the natural approach for such data. In contrast, the negative binomial regression model is much more flexible and is therefore likely to fit better, if the data are not Poisson.In example 8.30 we...

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The movement of a drunk guy – Random Walk and exponential regression

October 13, 2012
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The movement of a drunk guy – Random Walk and exponential regression

I was in a party last night and a guy was totally drunk. Not just the guy who had a few drinks and speaks a bit too loud, but the one who is not very likely to remember what he has done during his night, but who is rather very likely to suffer from a h...

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Two ways that correlation and stepwise regression can give different results

October 8, 2012
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In general, a correlation test is used to test the association between two variables (y and z). However, if there is a third variable (x) that might be related to z or y, it makes...

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Some regressions on school data

September 26, 2012
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Some regressions on school data

Eric and I have been exchanging emails about potential analyses for the school data and he published a first draft model in Offsetting Behaviour. I have kept on doing mostly data exploration while we get a definitive full dataset, and … Continue reading →

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Linear Regression using R

September 26, 2012
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Linear Regression using R

Regression Through this post I am going to explain How Linear Regression works? Let us start with what is regression and how it works? Regression is widely used for prediction and forecasting in field of machine learning. Focus of regression is on the relationship between dependent and one or more independent variables. The “dependent variable”

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Visually-weighted regression plots, with Zelig

September 25, 2012
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Visually-weighted regression plots, with Zelig

As a follow-up to yesterday’s post on producing visually-weighted regression plots, here is some code which illustrates the production of similar plots, but using Zelig’s convenient modeling and simulation functions. This code was produced...

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Simple visually-weighted regression plots

September 24, 2012
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Simple visually-weighted regression plots

There has recently been a lot of discussion of so-called “visually-weighted regression” plots. Folk hero Hadley Wickham suggests that such plots would be easy to implement with ggplot2, and so I have attempted to prove him right. The approa...

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Some helps for running and evaluating Bayesian regression models

September 21, 2012
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Around two years ago, I suddenly realized my statistical training had a great big Bayes-shaped hole in it. My formal education in statistics was pretty narrow – I got my degree in anthropology, a discipline not exactly known for its rigorously systematic analytic methods. I learned the basics of linear models and principal components analysis

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Confidence Regions for Regression Coefficients

September 16, 2012
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Confidence Regions for Regression Coefficients

Let’s consider the usual linear regression model, with the full set of assumptions:                     y = Xβ + ε ;    ε ~ N , (1)where X is a non-random (n × k) mat...

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