# 3793 search results for "gis"

## Spatial clipping and aggregation in R

January 10, 2014
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A common task in GIS is comparing the spatial extent of one layer with another. Say you have a load of points, some of which overlay a polygon layer. You are only interested in the points that intersect with the points. What do you do? Also, how can you aggregated-up the values contained in the points to correspond with the...

## Spatial clipping and aggregation in R

January 10, 2014
By

A common task in GIS is comparing the spatial extent of one layer with another. Say you have a load of points, some of which overlay a polygon layer. You are only interested in the points that intersect with the points. What do you do? Also, how can you aggregated-up the values contained in the points to correspond with the...

## Instrumental Variables Simulation

January 9, 2014
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Instrumental Variables Instrumental variables are an incredibly powerful for dealing with unobserved heterogenity within the context of regression but the language used to define them is mind bending. Typically, you hear something along the lines of “an instrumental variable is a variable that is correlated with x but uncorrelated with...

## Instrumental Variables Simulation

January 9, 2014
By

Instrumental Variables Instrumental variables are an incredibly powerful for dealing with unobserved heterogenity within the context of regression but the language used to define them is mind bending. Typically, you hear something along the lines of “an instrumental variable is a variable that is correlated with x but uncorrelated with...

## Calculating the Overlap of Two Normal Distributions Using Monte Carlo Integration

January 8, 2014
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I read this post over at the blog Cartesian Faith about Probability and Monte Carlo methods. The post describe how to numerically intregate using Monte Carlo methods. I thought the (…) Read more

## Calculating the Overlap of Two Normal Distributions Using Monte Carlo Integration

January 8, 2014
By

I read this post over at the blog Cartesian Faith about Probability and Monte Carlo methods. The post describe how to numerically intregate using Monte Carlo methods. I thought the results looked cool so I used the method to calculate the overlap of two normal distributions that are separated by a Cohen’s d of 0.8. You should head...

## Whale charts – Visualising customer profitability

January 7, 2014
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The Christmas and New Year's break is over, yet there is still time to return unwanted presents. Return to Santa was the title of an article in the Economist that highlighted the impact on online retailers, as return rates can be alarmingly high. The article quotes a study by Christian Schulze of the Frankfurt School...

## An Introduction to Statistical Learning with Applications in R

January 6, 2014
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Statistical learning theory offers an opportunity to those of us trained as social science methodologists to look at everything we have learned from a different perspective. For example, missing value imputation can be seen as matrix completion and rec...

## R vs Stata: Importing and Saving Datasets

January 6, 2014
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Today, I got a license of the new Stata/MP 13 (dual core), so I decided to make some succinct comparisons with R (Rstudio). Much more tests will come in the following weeks, but today I focused only on the basics: processing text files. Essentially, reading and writing raw datasets. The results I obtained, surprised me—I've

## PISA scores

January 6, 2014
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The Guardian Newspaper has an interesting article about the Pisa (Program for International Student Assessment) scores for 2012, and it includes data. Since I was interested to see how my own region scored, I downloaded the data into a file called PISA-summary-2012.csv and created a plot summarizing scores in all the sampled regions, with Canada highlighted. Graphical...