It’s that time of year, near the end of the semester, when I ask students to write down any questions they may have about material covered in the course. This semester I am teaching Advanced Quantitative Data Analysis. I thought other people might be interested in the answers to the questions students asked as well….
Anyone who has ever taught has probably had this experience … you are reading a student paper and think, “I really don’t understand what he/ she is trying to say here.” Like most professors, you probably assume that in these situations, the students aren’t very clear on the concepts themselves. You’re probably…
Today was a lesson in why one should always be a little leery of mean substitution. I had downloaded a data set to use as a logistic regression example for my class tomorrow. It happened to be the 2010 Monitoring the Future study and I was particularly interested in school drop out. This is a…
It’s about time I got some recognition ! You can claim your own Love Stats award here. Careful, of undeserved awards, though. The last person who falsely claimed a Love Stats award had multicollinearity in his measures, a high VIF and died of complications of homoscedasticity. You have been warned.
Giving a whole new meaning to “computing in the cloud”, I finished up my paper “A gentle introduction to survival analysis” for the Nevada SAS Users Group from 30,000 feet up using on-board wi-fi and SAS On-demand. I was shocked to find that the performance was much better in-flight. Presumably, if you charge people $12.95…
I might as well give you my opinion of these two kinds of sin as long as, in a way, against each other we are pitting them, And that is, don’t bother your head about the sins of commission because however sinful, they must at least be fun or else you wouldn’t be committing them….
Jon Peltier and I were going back and forth on twitter about why it is that people will post answers on a forum or mailing list that are completely incorrect. As Peter Flom says, “They are often in error but never in doubt.” Jon suggested there are three types; those who don’t know and admit…
Unfamiliar jargon like Kaplan-Meier curves, PROC PHREG, right-censored and hazard functions can be daunting to the newcomer. Survival analysis is really quite straightforward; it is simply a set of statistical techniques used when the focus is “time to event”. The event can be death, divorce, arrest, substance abuse or literally anything else. You’ve been wanting…
Next question on categorical data analysis … Correlated proportions. There are a lot of reasons why you might have correlated data in a two-way contingency table. The most common is that you have measured people twice. I have heard people say that including discussion of homosexuality in school makes it more likely that children…
The other day I wrote about how I had never had the need to do a binomial test for a proportion with SAS. In my business, at least, the question of whether the proportion in the population equals X just doesn’t come up very often. Actually, given that I had taught not one, but two…