Recently, someone asked me if I could explain chi-square in a few words. The short answer is, “No, I am incapable of using only a few words for any purpose whatsoever. If you doubt this, ask any of my children.” What is chi-square? Chi-square is a measure of relationship between two categorical variables. For example,…
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…
Statistics applies to everything. Today I was looking up examples of the Satterthwaite alternative to the pooled variance t-test. In short, a t-test is used when one wants to answer the question, “Is the difference between these two groups greater than one would expect to find by chance?” Any time you measure two groups, whether…
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…
SPSS does some pretty cool things, and I have written about some of them here. However, there are also some annoyances. First of all, it is one of the hardest packages to use moving datasets from one format or platform to another. The regular SPSS dataset, the one that ends in .sav crashes many mail…
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…
If you haven’t checked out the site 43thing.coms website, you really should. You can post up to 43 things that you want to do and then add updates as you make progress on your things. As no good idea should ever go uncopied, I decided to write a couple of posts on cool things about…
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…
Every now and then I post a mistake I made using either statistical software or statistics. Students often get discouraged feeling they make so many mistakes and they will never get it all right. No one gets it all right all the time. Obvious mistake of the day …. I was making minor cosmetic changes…
I have been asked several times by students in my classes if I would consider writing a blog on statistics and statistical programming. Apparently, blogs are “in” with people younger than me, as witness daughter #2 at left who has just informed me that people do not use the term “in” any more. Whatever. Giving…