Monthly Archives: February 2009

Video To Help Excel Users Get Familiar With R

I’ve made a short (9 minute) video to help Excel users get familiar with R.  This video gives a quick overview of the R user interface, demonstrates an R session and walks through a short R chart script. This video is for those Excel users who have heard about R and would like to get a better feel for how it works and what its like.

Here’s  a link to my Getting Familiar video.

Let me know what you think.

Temperature Anomaly Data Displays

Is there a single “best” way to display temperature anomaly data? The answer is obvious – NO! The best display depends on what we are trying to show.  Statistical charts compare one variable with one or more other variables.

Since our display option affects how we interpret the data, it is important to be clear on what we are comparing. In this post I want to show 3 ways to display temperature anomaly data and the implications that the display method has on our interpretation of the data. I’ll use a map, a trend chart and a dot plot. Continue reading

Time Series Regression of Global Temperature, El Nino – LaNina, and Volcanic Events

In a previous post, I showed how to make a 3 panel chart displaying RSS temperature anomalies,  El Nino- La Nina (NINO34 index) and volcanic event (SATO Index) time series data.  While time series charts can give a visual impression of how time series are related, time series regression provides much more information, including leading – lagging relationships between the time series.

In this post, I analyze the RSS, NINO34 and SATO time series using a simple trend line and a multiple regression model with lag periods for the independent variables. The post demonstrates some of  R ‘s regression analysis and data lagging capabilities. Links to the R script and data files are provided.

Continue reading

R Panel Chart Beats Excel Panel Chart

In this post, I show how to make a 3 variable time series panel chart in R. As an Excel panel chart pioneer, I can tell you that it is very difficult and messy to produce this type of panel chart in Excel.  The example R panel chart uses R’s a step chart format for one plot and R’s vertical line  format for the other 2 plots. Several of R’s dynamic capabilities, not inherently available in Excel, are also used. No helper series are needed and the chart can easily be regenerated each month as new data is available.

Here’s The R Panel Chart

First, let’s take a look at the chart to see what’s so good about R charting.

rss_3_panel Continue reading

R Script to Automatically Chart Web Based Global Temperature Data

This post shows an R script to automatically generate a trend chart from web based global temperature data.  The R script allows me to update my plot each month as soon as the source file is updated. The plot is self documenting so that the chart reader can see the data period,  the overall trend line, slope for trend line; the last data point is highlighted and value given. Date stamp and name are included in the margin. Continue reading