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In general, a statistical analysis of univariate data starts with a histogram. If the histogram doesn’t show a bell shape, the data probably does not follow a normal distribution. If the logarithm of the data plots as a normal histogram, then the data is lognormally distributed. Any statistical projections and parameter estimates are based on the normal distribution of the log of the data. This article focuses on the lognormal distribution and the lognormal probability plot.
The Variety of Statistical Tools to Support Your Decision MakingMy wife and I moved to a new home last year. We have yet to organize our tools.
The bedroom and kitchen are now organized. We, for the most part, can find the sweater or pan that we’re seeking.
No so for our tools in the shop. We have an assortment of hand tools for painting, home maintenance, yard work, and woodworking. In our previous home, we had the tools on pegboards, on shelves, in cabinets. We could find the right tool for the job at hand quickly. We’ve avoided the tool aisle at the hardware store recently, as we were sure we had the tool we need in the jumbled mess in our garage already. Still haven’t found it, though.
Have you noticed the number of statistical tools available? It’s like visiting a well-stocked tool store. There are basic tools like trend charting and advanced tools like proportional hazard models. Let’s explore the available tools a little so you can quickly find the right tool for the question or problem you are facing today. [Read more…]
With the kind permission of Wayne Nelson and Robert Abernathy we are posting an article on the analysis of repair data. As you may know, the assumptions made when using simple time to failure analysis of repairable systems may provide misleading results. Using the analysis method outlined by Wayne is one way to avoid those costly mistakes. [Read more…]