Monthly Archives:July 2009

Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

July 31,2009
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Simple visualization of a 11X5 table (for WordPress 2.9 Features Vote Results)

I guess this is not the number one post I would like to start with on this blog,but I feel the time is right for it (community-wise).I'll move on to the subject matter in a moment,but first a short intro: This blog is written by Tal Galili.I am ...

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Kruskal-Wallis one-way analysis of variance

July 31,2009
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If you have to perform the comparison between multiple groups,but you can not run a ANOVA for multiple comparisons because the groups do not follow a normal distribution,you can use the Kruskal-Wallis test,which can be applied when you can not make ...

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Analysis of variance: ANOVA,for multiple comparisons

July 30,2009
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Analysis of variance: ANOVA,for multiple comparisonsThe ANOVA model can be used to compare the mean of several groups with each other,using a parametric method (assuming that the groups follow a Gaussian distribution).Proceed with the following example:The manager of a supermarket chain wants to see if the consumption in kilowatts of 4 stores between them are equal.He...

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Comparison of two proportions: parametric (Z-test) and non-parametric (chi-squared) methods

July 29,2009
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Consider for example the following problem.The owner of a betting company wants to verify whether a customer is cheating or not.To do this want to compare the number of successes of one player with the number of successes of one of his employees,of w...

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Wilcoxon signed rank test

July 29,2009
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Non-parametric statistical hypothesis test,for the comparison of the means between 2 paired samplesThe mayor of a city wants to see if pollution levels are reduced by closing the streets to the car traffic.This is measured by the rate of pollution every 60 minutes (8am 22pm: total of 15 measurements) in a day when traffic is open,and...

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Beta Verson of tikzDevice Released!

July 28,2009
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The tikzDevice package provides a new graphics device for R which enables direct output of graphics in a LaTeX-friendly way.The device output consists of files containing instructions for the TikZ graphics language and may be imported directly into LaTeX documents using the \input{} command.The beta version of tikzDevice is now available here.An

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I know it's been so long…

July 28,2009
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Hey,I know it's been so long since last time I posted something in here,but I was really busy with my thesis and some other stuff,but now that I have more time I promise I'll post some interesting stuff in here,by the way,I found such an Interestin...

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Corpus Linguistics with R,Day 2

July 28,2009
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R Lesson 2 text gsub ("second","third",text) SEARCH-REPLACE-SUBJECT "This is a first example sentence." "And this is a third example sentence." __ gsub ("n","X",text) "This is a first example seXteXce." "AXd this is a secoXd example seXteXce." __ gsub ("is","was",text) "Thwas was a first example

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Corpus Linguistics with R,Day 1

July 28,2009
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(This post documents the first day of a class on R that I took at ESU C&T.I is posted here purely for my own use.) R Lesson 1 __ 2+3;2/3;2^3 5 0.6666667 8 --- Fundamentals - Functions __ log(x=1000,base=10) 3 --- (Formals describes the syntax of other

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Wilcoxon-Mann-Whitney rank sum test (or test U)

July 27,2009
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Comparison of the averages of two independent groups of samples,of which we can not assume a distribution of Gaussian type;is also known as Mann-Whitney U-test.You want to see if the mean of goals suffered by two football teams over the years is the same.Are below the number of goals suffered by each team in 6 games...

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