2810 search results for "GIS"

Monty Hall by simulation in R

February 3, 2012
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Monty Hall by simulation in R

(Almost) every introductory course in probability introduces conditional probability using the famous Monte Hall problem. In a nutshell, the problem is one of deciding on a best strategy in a simple game. In the game, the contestant is asked to select one of three doors. Behind one of the doors is a great prize (free

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Great Maps with ggplot2

February 2, 2012
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Great Maps with ggplot2

The above map (and this one) was produced using R and g

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Cochran Q Test for k related samples in R

February 1, 2012
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Cochran Q Test for k related samples in R

To run the Cochran Q Test in R, we need to download the package of it first, since it is not built-in in R. The name of the package is RVAideMemoire authored by Maxime Hervé. Here's how to do it.Codes:Here we are installing the package named RVAideMem...

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Confirming SSR, SSE, and SST using matrix in R

February 1, 2012
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Confirming SSR, SSE, and SST using matrix in R

The codes below was done in our regression laboratory class. Here, we run first the data in SPSS, and take the ANOVA output where we can find the computed values of SSR, SSE, and SST.ANOVAb Model Sum of Squares df Mean Square F Sig. 1 Regress...

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Example: Two Sample t-Test

January 31, 2012
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Example: Two Sample t-Test

The recovery time (in days) is measured for 10 patients taking a new drug and for 10 different patients taking a placebo. We wish to test the hypothesis that the mean recovery time for patients taking the drug is less than for those taking placebo. The...

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Given a room with n people in it, what is the probability any two will have the same birthday?

January 31, 2012
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Given a room with n people in it, what is the probability any two will have the same birthday?

Revisiting a fun puzzle I remember first encountering as an undergraduate. Nice example of creating a plot in R using ggplot2. I also plot the probability of someone in the room having the same birthday as you.

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Example: One Sample t-Test

January 31, 2012
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Example: One Sample t-Test

Using the stack loss dataset, test the hypothesis that the mean of the stackloss is equal to 20 versus a two-sided alternative. Solution:Codes:Output:Interpretation: With the p-value greater than the level of significance alpha at 0.05, then we la...

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Pre-conference tutorials announced for useR! 2012

January 30, 2012
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The worldwide R user conference, useR! 2012, will take place this year June 12-15 in Nashville, Tennessee. In addition to the regular program of invited and contributed talks, a highlight of every useR! is the pre-conference tutorials: hand-on, half-day in-depth expert-led sessions with a focused on a specific area of methodology with R. This year's roster of tutorials has...

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Categorizing my expenses

January 28, 2012
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Categorizing my expenses

In order to analyse my expenses, a classification scheme is necessary. I need to identify categories that are meaningful to me. I decided to go with the “Classification of Individual Consumption by Purpose” (COICOP), for three reasons:It is made by people who have thought more about consumption classification than I ever will. It is feasible to assign bank transactions...

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Say it in R with "by", "apply" and friends

January 28, 2012
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Say it in R with "by", "apply" and friends

Iris versicolor (Source: Wikipedia)R is a language, as Luis Apiolaza pointed out in his recent post. This is absolutely true, and learning a programming language is not much different from learning a foreign language. It takes time and a lot of pr...

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