Publications by Ralph
Variable selection using automatic methods
When we have a set of data with a small number of variables we can easily use a manual approach to identifying a good set of variables and the form they take in our statistical model. In other situations we may have a large number of potentially important variables and it soon becomes a time consuming effort to follow a manual variable selection ...
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Creating surface plots
A 3d wireframe plot is a type of graph that is used to display a surface – geographic data is an example of where this type of graph would be used or it could be used to display a fitted model with more than one explanatory variable. These plots are related to contour plots which are the two dimensional equivalent. To illustrate this type of gr...
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R Commander – a good introductory GUI for R
The R software is very powerful and flexible but one of the complaints of new users is that the learning curve is steep and can be daunting. There have been various projects to create GUIs for R with varying levels of sophistication, one of which is R Commander by John Fox. Fast Tube by Casper This interface is worth considering for beginners as ...
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R Commander – data manipulation and summaries
Previously we considered the R Commander interface as a simple GUI for the R statistical software system. Here we will look at how to undertake data manipulation and creating basic statistical summaries of data sets. Fast Tube by Casper The R Commander GUI has two menus “Data” and “Statistics” that are used for manipulating data sets and ...
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R Commander – hypothesis testing
The R Commander GUI can be used to perform classical hypothesis testing. There are menu options to undertake the variants on the t-test as well as tests on proportions or equality of variances for two samples of data. Fast Tube by Casper The “Statistics” menu provides access to various hypothesis tests via the “Means” sub-menu including: ...
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R Commander – linear regression
We can fit various linear regression models using the R Commander GUI which also provides various ways to consider the model diagnostics to determine whether we need to consider a different model. Fast Tube by Casper The “Statistics” menu provides access to various statistical models via the “Fit models” sub-menu including: Linear regres...
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R Commander – logistic regression
We can use the R Commander GUI to fit logistic regression models with one or more explanatory variables. There are also facilities to plot data and consider model diagnostics. The same series of menus as for linear models are used to fit a logistic regression model. Fast Tube by Casper The “Statistics” menu provides access to various statisti...
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R Commander – one-way analysis of variance
One way analysis of variance models can be fitted to data using the R Commander GUI. The general approach is similar to fitting the other types of model in R Commander described in previous posts. Fast Tube by Casper The “Statistics” menu provides access to some analysis of variance models via the “Means” sub-menu: One-way ANOVA – the ...
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R Commander – two-way analysis of variance
Two way analysis of variance models can be fitted to data using the R Commander GUI. The general approach is similar to fitting the other types of model in R Commander described in previous posts. Fast Tube by Casper The “Statistics” menu provides access to some analysis of variance models via the “Means” sub-menu: Multi-way ANOVA – th...
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Creating a Presentation with LaTeX Beamer – Getting Started
The LaTeX beamer package can be used to create appealing presentations for many applications. A working knowledge of LaTeX is required but once the initial learning curve and transition is made from a visual word processor to a markup based approach the benefits are worth the initial investment of time. Title Pages In a previous post we considere...
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