This page outlines some of the fundamental properties of SQL programming that you need to know as you start learning SQL. For example, SQL is a declarative language, meaning that you tell it what you want and not how to compute it. Also SQL syntax is not well-ordered, meaning that the order in which SQL statements are evaluated is not the same as the order that they appear. Continue reading
Category Archives: Statistics
PMean: Changing the font size in RStudio
Suppose you’re giving a talk and using R Studio. You want to make the fonts a bit larger so your audience can read them. It’s easy to do, once you know where to look. Continue reading
PMean: Changing the font size in R
This is one of those obvious things that’s not obvious when you need it most. Suppose I’m doing a demo of R for a group like our wonderful Kansas City R Users Group. I want to have a readable sized font. Here’s how you do it. Continue reading
PMean: Bad examples of data analysis are bad examples to use in teaching
I’m on various email discussion groups and every once in a while someone sends out a request that sounds something like this.
I’m teaching a class (or running a journal club or giving a seminar) on research design (or evidence based medicine or statistics) and I’d like to find an example of a research study that use bad statistical analysis.
And there’s always a flood of responses back. But if I were less busy, I’d jump into the conversation and say “Stop! Don’t do it!” Here’s why. Continue reading
Recommended: The Importance of Reproducible Research in High-Throughput Biology
I have not viewed this video yet, but have attended a similar talk and read a similar research paper by Keith Baggerly. His general message is that large biological and genetic experiments are sometimes designed so poorly as to invalidate the results. You can often discover these design flaws through a careful examination of the data sets themselves and their metadata. This process of uncovering design flaws is sometimes called “Forensic Statistics.” Continue reading
Recommended: Enrichment design studies should enhance signals of effectiveness.
I noticed several talks at the JSM 2016 on enrichment designs. I was only very vaguely familiar with what this meant, so I did a quick Google search. I found this very nice non-technical overview. Continue reading
Recommended: The Analysis of Biological Data, 2nd Edition
I have not seen this book, but it comes highly recommended by Frank Harrell, which is good enough for me. Continue reading
PMean: Never consult by email if you can help it
Consulting is always a back and forth process and often you will find yourself re-working things because of communication problems. That’s okay, but keep in mind that communication problems are even worse when they are done solely through email. Sometimes you have to consult this way, but it greatly increases the amount of rework needed. Here’s an example. Continue reading
PMean: Simple string substitutions
I had to make a rather complex string substitution for a project and I thought it would help to briefly review some simpler string substitution examples in R. You can find the R code at my github site. Continue reading
PMean: So you’re thinking about a systematic overview
If you are designing a systematic overview, you should talk to a statistician early in the process. There are lots of little things that you can do to make your research more rigorous. Here is a broad overview of these issues. Continue reading