In Preliminary Data Exploration in Excel I showed how to start the process of analyzing a table of data. The data I started with was a flat table, one row per observation, but it wasn’t normalized. That is, each input parameter had its own field. A more flexible arrangement is to replace the several fields [...]

A few well-designed charts, based on carefully manipulated data, can bring a lot of understanding to a set of data. This is an example taken from a manufacturing facility; the data has been obfuscated to protect any trade secrets, but then, I’ve been out of manufacturing for over five years.
The data consists of 71 mixtures; [...]

Yesterday we were treated to discussions about the visitor stats of several Excel bloggers:
Chandoo: June was Pointy Haired Dilbert Blog’s Best month ever
J-Walk’s Spreadsheet Page Blog: June Visitor Stats
Daily Dose of Excel’s June Stats
PTS Blog’s Web Stats – June 2009
Debra’s Contextures 200906 Site Stats
I thought it would be interesting to compare [...]

Chandoo’s Pointy Haired Dilbert blog had its best month ever in June, and he posted some stats to prove it. Congratulations, Chandoo!

Pointy Haired Dilbert statistics for June 2009

I’ve written a bit about regression and curve fitting; see Regression Approach to a Simple Physics Problem, Choosing a Trendline Type, and Trendline Fitting Errors. A blog reader asked for help with some sample data that he couldn’t fit. Here is the data.

I plotted the data and gave it the hairy eyeball. Not a linear [...]

Chandoo has posted the new Microsoft Ads in Microsoft says ‘I am PC’ and it is brilliant. Contrary to my expectations, especially after the abortive Bill and Jerry spots, I enjoyed these ads. Microsoft finally has countered those insipid Mac vs. PC ads (see review in Slate), in a tasteful and clever way. Hey, I [...]

In Graphical Approach to a Simple Physics Problem I discussed my daughter’s physics homework. The problem was to determine the relationships between how long it takes water to drain from a hole in the bottom of a bucket, the diameter of this hole, and the initial height of water in the bucket. The data is [...]

Several years ago I helped someone who was having trouble with a fitted trendline in an Excel chart. I saved the example, because I knew I’d have a blog someday, and I’d need a topic. I will use this example to describe a number of errors people encounter when fitting data. The errors are listed [...]

In Can You Improve this Graph Showing Suicide Rates in Japan?, Nathan of FlowingData shows a chart of long-term unemployment rates and suicide rates in Japan. The chart comes from Suicide Epidemic in Japan.

What’s wrong with this chart (which I’ve reproduced below)?

Axis label is faulty. “Japan and Suicide Rate” should be “Japan Long Term [...]

In my last post, Moving Averages, I made a bold comment that seasonally adjusted economic quantities used to intrigue me until I learned that they are merely moving averages. I said this only semi-seriously, and Rick Williams commented that seasonally adjusted averages really are seasonally adjusted, taking into account day of the week, month of [...]