This discussion goes to the heart of a subject which we don’t discuss nearly enough and that is interactions. In a predictive model there are typically what statisticians call ‘main effects’. A good example in medicine is the effect of particular medications. But sometimes medications in combination potentiate (or neutralize) each other. In other words [...]
To continue, we need to define a couple of terms. The first is a probability density function and the second is a sampling distribution.A probability density function expresses a particular function in terms of integrals. Thus for a frequency distribution smoothed (over repeated sampling) to form a curve as shown below, the area under the [...]
A hypothesis is a supposition made as a basis for research or reasoning without regard for its truth. So says the Oxford dictionary. What starts the hypothesis testing process is just such a supposition. In the justice system example we made, there is a supposition on the part of law enforcement that the apprehended person [...]
June marked the 25th anniversary of the publication of Dr. W. E. Deming’s first management book, “On Quality, Productivity and Competitive Position”. Deming lived both in Washington D. C. and New York where he kept an apartment on Hudson St. in the Village. He was a professor at NYU’s Graduate School of Business Administration from [...]
When discussing hypothesis testing, I have, from time to time, used the example of the criminal justice system to act as a metaphor for the logic and philosophical issues involved. It remains a good way to pose the logical dilemmas and the types of errors involved and to also discuss the idea of a system [...]
