1244 search results for "Excel"

Visualization in regression analysis

February 23, 2012
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Visualization in regression analysis

Visualization is a key to success in regression analysis. This is one of the (many) reasons I am also suspicious when I read an article with a quantitative (econometric) analysis without any graph. Consider for instance the following dataset, obtai...

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Example 9.21: The birthday "problem" re-examined

February 23, 2012
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Example 9.21: The birthday "problem" re-examined

The so-called birthday paradox or birthday problem is simply the counter-intutitive discovery that the probability of (at least) two people in a group sharing a birthday goes up surprisingly fast as the group size increases. If the group is only 23 peo...

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Visualization in regression analysis

February 23, 2012
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Visualization in regression analysis

Visualization is a key to success in regression analysis. This is one of the (many) reasons I am also suspicious when I read an article with a quantitative (econometric) analysis without any graph. Consider for instance the following dataset, obtained from http://data.worldbank.org/, with, for each country, the GDP per capita (in some common currency) and the infant mortality rate...

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A Heartfelt Thank You and the Resulting GSoC Project

February 21, 2012
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A Heartfelt Thank You and the Resulting GSoC Project

PerformanceAnalytics has long enjoyed contributions from users who would like to see specific functionality included. Diethelm Wuertz at ETHZ, who is the author and sponsor of all the various R/Metrics packages is one of those contributors. I first met Diethelm when he hosted a conference on high-frequency data in the early 1990′s (where we fretted

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Reflect your Personnel Selection: R & Taylor-Russell Tables

February 16, 2012
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Reflect your Personnel Selection: R & Taylor-Russell Tables

Taylor-Russell tables (Taylor & Russell, 1939) are designed to estimate the percentage of future employees who will be successful on the job if a particular selection method (eg. test, assessment center, interview) is used. I have already described the kibit … Weiterlesen →

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XLConnect 0.1-8

February 16, 2012
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XLConnect 0.1-8

Mirai Solutions GmbH (http://www.mirai-solutions.com) is pleased to announce the availability of XLConnect 0.1-8 on CRAN. The most prominent new features/extensions are an improved package vignette which provides more information and examples to get people started with the package. A new … Continue reading →

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Beware the Friedman test!

February 14, 2012
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Beware the Friedman test!

In section 10.4.4 of Serious stats (Baguley, 2012) I discuss the rank transformation and suggest that it often makes sense to rank transform data prior to application of conventional ‘parametric’ least squares procedures such as t tests or one-way ANOVA. There are several advantages to this approach over the usual approach (which involves learning and applying a new test such as Mann-Whitney U,

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Machine Learning Examples in R

February 12, 2012
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Machine Learning Examples in R

This is a post that has been a long time in the making. Following on from the excellent Stanford Machine Learning Course I have made examples of the main algorithms covered in R.We have Linear RegressionFollowed by Neural NetworksAnd Support ...

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Revisiting homicide rates

February 10, 2012
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Revisiting homicide rates

A pint of R plotted an interesting dataset: intentional homicides in South America. I thought the graphs were pretty but I was unhappy about the way information was conveyed in the plots; relative risk should be very important but number … Continue reading →

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managing projects using RStudio

February 10, 2012
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managing projects using RStudio

We're continually amazed with new developments within RStudio, the integrated developed environment for R that we highlighted previously (Among others, Andrew Gelman agrees with us about its value). The most recent addition addresses one of our earlie...

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