Going from the phi coefficient to odds-ratios. Remember the numerator for the phi coefficient was well, the odds ratio is the same two numbers DIVIDED rather than subtracted. You might think it is four numbers, but really it is not. The first number is the product of the diagonal cells (see below). The second number…
Yes, I am the F-word – a feminist. I was at a faculty meeting this weekend and one of the presenters began by saying, pointing to a colleague in the audience, “I am sure Dr. Y knows more about this than me.” Several times in her presentation on analysis of assessment data she would pause…
I hate SQL. This is probably completely irrational, like that guy I turned down for a date in junior high school who my mom always tells me founded a very successful company and is making piles of money. No wait, it wasn’t irrational, he always tried to copy off me in Algebra, plus he was…
Today, Dr. De Mars is — happy. One of the fun things about my job is that I get to do lots of different things. That can be a bit troubling some days, because statistical software consultant encompasses a wide range from different types of models, to coding, to various operating systems to all of…
Regularly, I search the Internet (well, not all of it) for signs of intelligent life. Most of what I find, sadly, falls into the category of blogs-on-what-I-ate-for-lunch. Every now and then, I get lucky. For example, Guy Kawasaki’s blog on How to change the world. Sometimes it is a little too self-impressed, but his writing…
Over the past twenty-five years, due to improvements in statistical software capabilities, it has become increasingly easier to obtain output for complex statistical procedures. Unfortunately, this does not mean that statistical analysis has become easier. In a relatively short period, it is possible to train an employee or student to be competent at getting computers…
Today, I had an epiphany. As I was reading a book on statistical modeling, I read a statement I had read dozens of times before about how beta-weights are partial derivatives and the light went off as I thought, “Duh, of course! I can’t believe I have never realized this. It is so obvious. OF…
The General Linear Model is general (also linear and a model, but that is another topic). What is general about it? What does it do? One way to try to understand a statistic is by the underlying mathematics. I read a paper today where most of it was written in Greek. Seriously. There were a…
Here’s a clever idea — Let’s say you want to predict who dies within the next year (I bet you are a lot of fun at parties). Moreover, you have a hypothesis to test that married people are less likely to die than single people. There are a number of factors that relate to both…
Out of all the thousands of pages of all of the textbooks you ever read in your life, how many sentences can you remember? One that has remained with me for over twenty years was in the required book for my inferential statistics course, “If something exists, it must exist in some quantity and that…