Who was it that said asking a statistician about sample size is like asking a jeweler about price. If you have to ask, you can’t afford it. We all know that the validity of a chi-square test is questionable if the expected sample size of the cells is less than five. Well, what do you…
Recall that in the last post we were using SAS functions to score a test that had been completed by middle school and upper elementary students. Since we wanted to make it as easy as possible for students to enter their answers, we accepted just about any format. Picking up where we left off ……
Did you ever fill out one of those online forms where you kept trying to submit it and got messages like, “You need to enter your phone number in the format 311-234-12234” or You cannot have any special characters in this field. That one really irritates me because, in fact, my last name has a…
On twitter, there were a few comments from people who said they didn’t like to take interns because “More than doing work, they want to watch me work.” I see both sides of that. You’re busy. You’re not netflix. I get it. On the other hand, that’s a good way to learn. The data are…
It’s after midnight and officially the weekend so it’s time for the sixth installment of Mama AnnMaria’s Guide to Not Getting Your Sorry Ass Fired. Click here for all of my advice on getting fired and quitting. Click here to buy the games I make on my day job. As I was saying … there are…
How common is a particular disease or condition? It depends on what you mean by common. Do you mean how many people have a condition, or do you mean how many new cases of it are there each year? In other words, are you asking about the probability of you HAVING a disease or of you GETTING…
Even though Rick Wicklin (buzzkill!) disabused me of the concern that SAS was communicating with aliens through the obscure coding in its sashelp data sets, I still wanted to roll my own. If you, too, feel more comfortable with a data set you have produced yourself, let me give you a few tips. There is…
I was going to write about prevalence and incidence, and how so-called simple statistics can be much more important than people think and are vastly under-rated. It was going to be cool. Trust me. In the process, I ran across two things even more important or cooler (I know, hard to believe, right?) Here’s what…
I’ll be teaching a graduate course in epidemiology in the spring and giving a talk on biostatistics at SAS Global Forum in April, so I thought I’d jump ahead and start rambling on about it now. When I tell people that I teach epidemiology, the first question I usually get is, What’s epidemiology? In short,…
This is something that has bothered me for a long time. When I read tables and reports from the National Center of Education Statistics (yes, I do, don’t judge me!), it makes it sound as if all is well with rural education. According to this table, for example, 100% of rural schools have at least…