1568 search results for "regression"

R in Google Summer of Code 2012

March 23, 2012
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This post is a slightly revised (and "blogified") version of the message Brian Peterson has sent to various R mailing lists.Once again, R has been accepted as a mentoring organization for the Google Summer of Code (2012).  We invite students interested in this program to learn more about it.  A good starting point...

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Example 9.24: Changing the parameterization for categorical predictors

March 22, 2012
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Example 9.24: Changing the parameterization for categorical predictors

In our book, we discuss the important question of how to assign different parameterizations to categorical variables when fitting models (section 3.1.3). We show code in R for use in the lm() function, as follows:lm(y ~ x, contrasts=list(x,"contr.trea...

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Nordic Countries Dominate the World in Internet Penetration

March 21, 2012
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Nordic Countries Dominate the World in Internet Penetration

Something about that cold weather... The number of internet users in the Nordic countries has greatly outpaced the world by comparison. Denmark, Iceland, Norway, Sweden, Finland - all in the elite echelon. These countries share a common ancestry -...

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Using R for a salary negotiation–an extension of decision tree models

March 21, 2012
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Using R for a salary negotiation–an extension of decision tree models

Let’s say you are in the middle of a salary negotiation, and you want to know whether you should be aggressive in your offering or conservative. One way to help with the decision is to make a decision tree. We’ll work with the following assumptions: You are at a job currently making $50k You have the choices between...

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Survey in R course taught by Thomas Lumley at Statistics.com

March 19, 2012
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Statistics.com is offering a new online course, “Survey Analysis in R,” debuts March 23 – April 20, with Dr. Thomas Lumley. Dr. Lumley is the creator of the R package “Survey,” and the author of the course text – “Complex Surveys: A Guide to Analysis Using R.” The course is suitable for those with some familiarity with R and...

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Liking of apples – more than juiciness

March 18, 2012
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Liking of apples – more than juiciness

In a previous blog it was shown using literature data that liking of apples was related to juiciness. However, there were some questionsIs the relation linear or slightly curved? The variation in liking around CJuiciness is large. Are more explana...

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Predicting Marketing Campaign with R

March 17, 2012
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Predicting Marketing Campaign with R

In my last blog I created a mechanism to fetch data from Salesforce using rJava and SOQL. In this blog I am going to use that mechanism to fetch ad campaign data from salesforce and predict future ad campaign sales using R Let us assume that Salesforce has campaign data for last eight quarters.  This

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Solving easy problems the hard way

March 17, 2012
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Solving easy problems the hard way

There’s a charming little brain teaser that’s going around the Interwebs. It’s got various forms, but they all look something like this: This problem can be solved by pre-school children in 5-10 minutes, by programer – in 1 hour, by people with higher education … well, check it yourself!  8809=6 7111=0 2172=0 6666=4 1111=0 3213=0 7662=2 9313=1 0000=4 2222=0 3333=0 5555=0 8193=3 8096=5 7777=0 9999=4 7756=1 6855=3 9881=5 5531=0 2581=? SPOILER ALERT… The answer has to do with how many

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NIT: Fatty acids study in R – Part 006

March 12, 2012
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NIT: Fatty acids study in R – Part 006

In one of the columns, for constituent C16_0, one sample (57) has a value of “zero” (we could see this in the histogram).The reason for that is that the laboratory did not supply this value. The PLS regression will consider the lab value as cero, s...

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NIT: Fatty acids study in R – Part 005

March 9, 2012
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NIT: Fatty acids study in R – Part 005

There are several algorithms to run a PLS regression (I recommend to consult the books: “Introduction to Multivariate Analysis in Chemometrics - Kurt Varmuza & Peter Filzmozer” and “Chemometrics with R – Ron Wehrens”).We are going to use ...

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