I don’t know any statistics, but I’m thinking about trying something which probably requires that I ought to know something about statistics.
Suppose I have a chart with the following columns:
Classroom; Semester; Grade; Course; Instructor
The content of the first and second columns are probably obvious. The third column, in case it’s not obvious, would contain the average grade awarded for whatever course met in that classroom in that semester. Columns four and five I take it are also obvious.
And say I find that the grades in classroom A average out to 3.2 (on the four point scale) while the average of all classrooms is 3.3.
Some questions, and if these are completely clueless questions please feel free to berate me, but I’d like to know if this is something I can easily just pick up on how to do. If you think anyone with half a brain should be able to figure out how to do this him or herself, feel free to berate me about that as well. I plead twins, workload, and a history that includes no statistics education whatsoever. Anyway, the questions are:
- How do I know whether the size of the effect is large enough to be significant?
- How do I do the whole “correcting for” thing I always read about in reports on statistical measurement? For example, correcting for the course in the sense of trying to see if the difference in scores is due to the course or instructor rather than the classroom?
- Aside from the other two questions, are there any really snazzy things I should be able to do with this data?