Ok Readers, let's take a run at another DonorsChoose Challenge!

Wow! Thanks to all of you readers who stepped up to give little kids in Maine a carpet to sit on, instead of a dirty, wet linoleum floor.

Now here’s a chance to help some big kids. High school students in a high poverty school in Gaffney SC need materials for dissections.

My Anatomy and Physiology students attend a high poverty school that has limited resources and monies available. They are juniors or seniors who have identified their career path to be in the health science field. Some have set goals to be lab technicians while others strive for their doctorates. All of them want to learn and are interested in the structure and function of the human body. We have an enormous amount of fun learning and utilizing the limited resources we have.

Sure, and I remember the lab demos from my science classes the best. Exploding stuff and thermogenic reactions. Inclined planes, air tables and dropping shit. From biology, the dissections. Are you any different?

Let’s try to give these kids an experience they will remember when they are at my ripe old age…

My students need dissection specimens, like 40 sheep eyes, 40 sheep hearts, 40 sheep half brains, and dissection supplies to conduct essential labs in anatomy class.

Remember, every little bit counts. Can you spare $5? Even if you gave your bit already, pass along the link. Ask your Facebook friends to donate. Twitt your Tweeps.

It’s for the next generation. Don’t you want them to know a little something when they come to re-insert your catheter at Happy Golden Acres? I know you do.

Give. Your urethra will thank you later.

ANOVA and the test of normality

One still occasionally gets whinging from some corner or other about not being able to run Analysis of Variance statistical procedures (ANOVA) because the data didn’t pass a test of normality. I.e., a test of whether they appear to fit a normal distribution.

Paper reviewers, trainees, colleagues….this can come from any corner. It betrays a grad-school class level of understanding of what statistical analysis of data is supposed to do…but not a grasp of what it is doing for us at a fundamental level within the conduct of science.

Your stock response should be “the ANOVA is robust against violations of normality, move along“.

I note that the company GraphPad, which makes the Prism statistical/curve fitting package beloved of behavioral pharmacologists, has a tidy FAQ answer.

The extract version:

A population has a distribution that may be Gaussian or not. A sample of data cannot be Gaussian or not Gaussian. That term can only apply to the entire population of values from which the data were sampled…In almost all cases, we can be sure that the data were not sampled from an ideal Gaussian distribution… an ideal Gaussian distribution includes some very low negative numbers and some superhigh positive values…When collecting data, there are constraints on the possible values…Other variables can…have physical or physiological limits that don’t allow super large values… plenty of simulations have shown that these tests work well even when the population is only approximately Gaussian…It is hard to define what “close enough” means, and the normality tests were not designed with this in mind.