Is the reciprocal of a positively skewed distribution also positively skewed?

@RISK (risk analysis using Monte Carlo, software for Excel) can be a simple yet effective tool to explore statistical concepts and properties of distributions.  For example, one interesting question is whether the reciprocal of a positively skewed distribution is positively or negatively skewed. One’s first thought may be that such a reciprocal is negatively skewed. […]

Palisade Corporation Exhibiting at the ASQ Lean Six Sigma Conference

During these deteriorating economic times, it is more important than ever for organizations to be more vigilant about cutting costs and boosting the bottom line. An option is to instill a Lean and Lean Six Sigma culture when tackling projects to save money. The American Society for Quality (ASQ) is once again hosting the 2009 […]

Weeds and Want

Cheatgrass.  Invasive mussels.  A brown tree snake.  They are "exotic,"  they are "weedy," and they are just a few of the invading culprits the USDA hopes to subdue with grants amounting to $4.4 million to fourteen U.S. universities.   Weeds do, in fact bring want.  According to the USDA, more than 50,000 weedy species have been […]

Correlation and Co-integration

As mentioned in an earlier posting, correlation models do not necessarily capture the directionality between variables.  We showed an example where asset prices whose changes are positively correlated may still trend in opposite directions. Co-integrated time series, are becoming more and more important in financial econometrics, and attempt to capturing the directionality between variables.  This […]

Monte Carlo Simulation: An Underutilized Six Sigma Tool

Lean Six Sigma projects are performed in many areas of business. There are a few that require an estimation of future performance when there is no chance to test or evaluate the new process. On February 26, Rick Haynes of SmarterSolutions  will share his expertise in a free live webcast that documents a case where […]

Correlation and Directionality

This is the second in a series of postings about correlation modelling.  In the first posting we discussed the idea of correlation as representing a proxy model of dependency between random variables. In this posting, we discuss the idea the often overlooked concept that relationships of correlation do not necessarily imply any directionality. In modelling […]

Okay, Charlie, Where do we go from here?

Two hundred years ago yesterday Charles Darwin was born.  It was the midst of the Industrial Revolution, and machines had just begun to replace human labor.  Darwin had some formal medical education and a good bit of informal scientific education.  He also had an imagination powerful enough to envision the links between geological time and […]