In fantasy land and fairy tales, there is this thing called equivalent groups. People are randomly assigned to a control group and a treatment group. Everyone in the treatment group receives the same treatment, for example, being sprinkled with exactly three teaspoons of fairy dust, and everyone in the control group does not….
I tried to find an easily comprehended explanation of the F-statistic for my students but I could not, so, here as a public service is mine. If you have some other pages you can recommend, please let me know. Okay, why ANOVA? Why not just do a t-test? Well, let’s say you have five groups….
Last month, I wrote about the steps to solving any statistics problem. A Pew Research Poll asked 1,201 adults “All in all, do you think affirmative action programs designed to increase the number of black and other minority students on campus are a good thing or a bad thing? Sixty percent said good, 30% said…
Here we have analysis of open data using free software with – uh, SAS? Click the links below and watch the videos. Seriously. They are too large to embed in the post. Sorry. Yes, you might think of SAS as the choice of multinational corporations with unlimited software budgets. You now have two options, if…
I admit that some months I am so busy that I toss Significance out without reading it – this is the magazine of the American Statistical Association (ASA) and Royal Statistical Society. No, I don’t pile up things to read later because I never do read them later. Anyway … taking two days off work,…
The past couple of weeks, I’ve been hearing my friends from Turtle Mountain and Spirit Lake talk about the election in North Dakota. I was particularly interested because this was the one election that Nate Silver predicted incorrectly. He had Heitkamp down by 3.9 percent, and yet she won. I have no idea how Silver’s…
Last week, teaching my statistics class, I gave an example of regression using actual data. I had hypothesized that given the greater discrimination and poverty on the reservation 40 or 50 years ago, there would be a negative relationship between age and educational attainment within the adult population. That is, people over 60 would be…
What do you see when you look at a regression analysis? Because me, all I see is a bunch of numbers and I have no idea where to look first or what’s important. Could you start me off with regression in some baby steps? What is it that you are looking at when you stare…
While about equal percentages of the general public will be either happy or upset with the outcome of the presidential and congressional elections, 100% of statisticians will be cheering Nate Silver. The reason I’ve watched Silver’s blog very closely is because I’m a big believer in the Central Limit Theorem, which states that the mean…
Today, I wanted to find the confidence interval for the difference between two proportions. I have SAS, SPSS, Stata, JMP, Excel and God knows what else laying around. I did not want to go to the effort of plugging the numbers into a calculator, but it really is a pretty straightforward formula, so you would…