Some problems that seem really complex are quite simple when you look at them in the right way. Take this one, for example: My hypothesis is that a major problem in math achievement is persistence. Students just give up at the first sign of trouble. I have three different data sets with student data from the Spirit…
Let’s get this out right up front – I have no question that there is discrimination in the tech industry. I gave an hour-long talk on this very subject at MIT a couple of weeks ago, where I pointed out that everyone’s first draft of pretty much everything is crap – your first game, first…
You wouldn’t think there would be that much to say about scree plots. That is because you are like me and sometimes wrong. The problem I often have teaching is that I assume people know a lot more than is reasonable to expect for someone coming into a course. Sometimes, I’m like a toddler who…
I find this scree plot of eigenvalues very helpful in identifying the number of factors. A scree plot is a plot of the eigenvalues by the factor number. I realized this is only helpful if one understands what an eigenvalue is. First of all, go way back to Stat 101 & remember that correlation is…
I read this in a review of a study on teacher expectancy effects but it could really apply to so many other studies. If these results bear any relationship at all to reality, it is indeed a fortunate coincidence. Those of us who choose careers in research like to believe that it is all like…
In assessing whether our Fish Lake game really works to teach fractions, we collect a lot of data, including a pretest and a post-test. We also use a lot of types of items, including a couple of essay questions. Being reasonable people, we are interested in the extent to which the ratings on these items…
Sometimes, you can just eyeball it. Really, if something truly is an outlier, you ought to be able to spot it. Take this plot, for example. It should be pretty obvious that the vast majority of our sample for the Fish Lake game were students in grades, 4, 5 and 6. Those in the lower…
Previously, I discussed PROC FREQ for checking the validity of your data. Now we are on to data analysis, but, as anyone who does analysis for more than about 23 minutes can tell you, cleaning your data and doing analysis is seldom a two-step process. In fact, it’s more like a loop of two steps,…
I’m in the middle of data preparation on a research project on games to teach fractions. This is the part of a data analysis project that takes up 80% of the time. Fortunately, PROC FREQ from SAS can simplify things. 1. How many unique records ? There are multiple quizzes in the game, and you…
In the past, I have questioned the extent to which we really suck at math in the U.S. While I’m still a bit skeptical that the average child in developing countries is doing dramatically better than children in the U.S., one thing is pretty clear from our results to date, and that is that the…