# 1091 search results for "latex"

## Supervised Classification, beyond the logistic

March 5, 2015
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In our data-science class, after discussing limitations of the logistic regression, e.g. the fact that the decision boundary line was a straight line, we’ve mentioned possible natural extensions. Let us consider our (now) standard dataset clr1 <- c(rgb(1,0,0,1),rgb(0,0,1,1)) clr2 <- c(rgb(1,0,0,.2),rgb(0,0,1,.2)) x <- c(.4,.55,.65,.9,.1,.35,.5,.15,.2,.85) y <- c(.85,.95,.8,.87,.5,.55,.5,.2,.1,.3) z <- c(1,1,1,1,1,0,0,1,0,0) df <- data.frame(x,y,z) plot(x,y,pch=19,cex=2,col=clr1) One can consider a quadratic...

## Supervised Classification, discriminant analysis

March 3, 2015
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Another popular technique for classification (or at least, which used to be popular) is the (linear) discriminant analysis, introduced by Ronald Fisher in 1936. Consider the same dataset as in our previous post > clr1 <- c(rgb(1,0,0,1),rgb(0,0,1,1)) > x <- c(.4,.55,.65,.9,.1,.35,.5,.15,.2,.85) > y <- c(.85,.95,.8,.87,.5,.55,.5,.2,.1,.3) > z <- c(1,1,1,1,1,0,0,1,0,0) > df <- data.frame(x,y,z) > plot(x,y,pch=19,cex=2,col=clr1) The main interest of...

## Plotly Graphs with Domino’s New R Notebook

March 3, 2015
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by Matt Sundquist co-founder of Plotly Domino's new R Notebook and Plotly's R API let you code, make interactive R and ggplot2 graphs, and collaborate entirely online. Here is the Notebook in action: Published R Notebook To execute this Notebook, or to build your own, head to Domino's Plotly Project. The GIF below shows how to get started: choose...

## Supervised Classification, Logistic and Multinomial

March 2, 2015
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We will start, in our Data Science course,  to discuss classification techniques (in the context of supervised models). Consider the following case, with 10 points, and two classes (red and blue) > clr1 <- c(rgb(1,0,0,1),rgb(0,0,1,1)) > clr2 <- c(rgb(1,0,0,.2),rgb(0,0,1,.2)) > x <- c(.4,.55,.65,.9,.1,.35,.5,.15,.2,.85) > y <- c(.85,.95,.8,.87,.5,.55,.5,.2,.1,.3) > z <- c(1,1,1,1,1,0,0,1,0,0) > df <- data.frame(x,y,z) > plot(x,y,pch=19,cex=2,col=clr1) To get...

## R Markdown Tutorial by RStudio and DataCamp

March 1, 2015
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In collaboration with Garrett Grolemund, RStudio’s teaching specialist, DataCamp has developed a new interactive course to facilitate reproducible reporting of your R analyses. R Markdown enables you to generate reports straight from your R code, documenting your works as an HTML, pdf or Microsoft document. This course is part of DataCamp’s R training path, but can The post

## Using Tables for Statistics on Large Vectors

March 1, 2015
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$Using Tables for Statistics on Large Vectors$

This is the first post I’ve written in a while. I have been somewhat radio silent on social media, but I’m jumping back in. Now, I work with brain images, which can have millions of elements (referred to as voxels). Many of these elements are zero (for background). We want to calculate basic statistics on

## One weird trick to compile multipartite dynamic documents with Rmarkdown

February 28, 2015
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This afternoon I stumbled across this one weird trick an undocumented part of the YAML headers that get processed when you click the ‘knit’ button in RStudio. Knitting turns an Rmarkdown document into a specified format, using the rmarkdown package’s render function to call pandoc (a universal document converter written in Haskell). If you...

## Visualizing Clusters

February 24, 2015
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Consider the following dataset, with (only) ten points x=c(.4,.55,.65,.9,.1,.35,.5,.15,.2,.85) y=c(.85,.95,.8,.87,.5,.55,.5,.2,.1,.3) plot(x,y,pch=19,cex=2) We want to get – say – two clusters. Or more specifically, two sets of observations, each of them sharing some similarities. Since the number of observations is rather small, it is actually possible to get an exhaustive list of all partitions, and to minimize some criteria, such...

## k-means clustering and Voronoi sets

February 22, 2015
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$k$

In the context of -means, we want to partition the space of our observations into  classes. each observation belongs to the cluster with the nearest mean. Here “nearest” is in the sense of some norm, usually the (Euclidean) norm. Consider the case where we have 2 classes. The means being respectively the 2 black dots. If we partition based...