Maybe I have been wrong. It wouldn’t be the first time, in fact, most of the really great things in my life have come about when I realized I was on the wrong track and took a sharp right turn. (Uncharacteristically skipping the opportunity here to make snarky comment about my first boyfriend, job or…
Everybody is talking now about the acquisition of SPSS by IBM. So far, having just come back from the SPSS DIrections conference, I can’t say that I have seen a lot of differences yet. There seemed like there were a few more SPSS people at the conference, which is a good thing. In my experience,…
I’ve been asked several times what made me change my mind about SAS Enterprise Guide. SAS EG and my husband have a lot in common. For one thing, neither made a great first impression. When I first met Dennis and saw that he was the same size as me (which my third daughter says is…
The model is non-significant, therefore my theory is supported. Huh? Just when you thought it was safe to get back into statistics… It took you two years of graduate school but now you have it down. P-value low = good, relationship detected, publication, tenure, Abercrombie & Fitch models at your feet. P-value = high, no…
Lately I have been on a roll looking at relatively less common statistical techniques, proportional hazards, survival analysis, etc. In keeping with that, I have been taking a look at propensity score matching, fondly known as PSM by, – well, by no one actually. The problem to be solved …. Think about some of these…
What is an event history model? Think of it like this – you are interested in whether something happens, what predicts whether it happens and how long until it happens. Let’s take a common one, like, say, death. An event history model could predict the duration from diagnosis of tuberculosis to death. In this model…
Here is how the Wald statistic works: You divide the maximum likelihood coefficient estimate by its standard error and square the result. If you wanted to be really specific about it, what you are dividing is the difference between the obtained coefficient estimate and your hypothesized estimate. I would say, though, that 99% of the…
Because I am no fun at all, as any of my children can tell you, I do not have a post for April Fool’s Day (although you should totally check out the blog on SAS for the Wii ). Being counter-cyclical can be good at times, for example, making money on your investments last year….
Logistic regression is based on logarithms. Ordinary Least Squares regression and analysis of variance uses the actual values as the dependent and independent variables in an equation. Logistic regression does not. What is a log, anyway? Let’s start with the very basics. First we learned to add: 5+5+5+5 = 20 After about eight years of…
Categorical data analysis used to be simple. You had two nominal variables and you did a chi-square analysis. If it was statistically significant, that was all it took to make life good. Then, logistic regression came along, with the reasonable notion that: A. Dichotomous choices such as bought a candy apple/ate tofu & bean sprouts…