- I guess I am commenting on the statistical perspective, at least, to start with.
On Fri, 23 Nov 2001 16:22:46 GMT, "L.C." <[EMAIL PROTECTED]> wrote: > The question got me thinking about this problem as a > multiple comparison problem. Exam scores are typically > sums of problem scores. The problem scores may be > thought of as random variables. By the central limit theorem, > the distribution of a large number of test scores should look > like a Normal distribution, and it typically (though not always) > does. Hence the well known bell curve. (Assume, for the sake > of argument that it holds here.) > The tests that I took throughout elementary and high school (grades 1-12) were certainly not 'normally distributed' or my scores would have had variation. Tests or homework: everything was truncated at the top. Consistency seems to be demanded by the system of putting in a 90-point cutoff for A. If the average were 75 or 80, a top score of 100 has 1/3 or 1/4 the effect of tossing in a bottom score of 0. (This does seem more appropriate as a 'meta-lesson' at the elementary level, that it would be at the college level. That is, I can see where it can be more appropriate to judge college students by best-performance, or end-of-term performance, where, for el-hi students, doing nothing but preparatory work, the *consistency* is part of the lesson.) I suppose that elementary textbooks *might* be calibrated so that hitting 90% of the answers correct is what ought to justify an A. - In that case, my teachers *might* have been judged by whether they assigned the easier questions or the tougher ones. The teachers did use some discretion in what they assigned. I do believe that my teachers did not put many really tough questions on a test or in homework BECAUSE that would 'bring down the average' -- and they did not have any other accepted model to use except the 90-point-A model, and they wanted to give a 'proper' proportion of A's. As a consequence, I arrived at college without ever learning to study. No course had ever placed any demand on me. The usual notion of 'grading on the curve' before college was that a teacher would give more A's than the 90-point model would justify; so we students tended to want it. But I don't remember it happening much at all. I first matriculated at Rice where the freshman classes were huge, and were pre-announced as being 'on the curve' -- though the cutoffs were not absolutely fixed in advance. After making test scores like 35 and 4 (out of 100), I could *learn* from the scoring. I don't think I would have learned to 'show my work' -- at least, not so quickly and dramatically -- if I had not had that 4 on a physics test. With the curve, and low, low averages, you do notice that a single *good* performance can outweigh several poor ones. So that is good. Now, in the NY Times, just a week or two ago. The dean of undergraduates at Harvard has a complaint about grade inflation. More than 48% of all undergraduate grades last year were A. (In 1986, it was only 34% or so.) Only 6% or present grades were C or D or F. The dean has asked the faculty to discuss it, which is as much as she can do. I don't know: Would the A's emerge as scores on-a-curve, or are the lessons so easy that all the answers are right? What is the purpose of an A, anyway? There are relatively few courses where the grade is matched against an outside criterion. When I think about it, I don't think the existence of the outside criterion is apt to matter. Law school -- state exams are a breeze in a few states, or they can be almost impossible. Different schools in the state will have different standards, I am sure. Medical boards, on the other hand, are national, and I think they are usually passed by decent students. But I don't think of the MDs I have known as being obsessed about the college boards that they, personally, passed some years ago. I think the professors in either sort of school have standards from elsewhere for the grades they assign. -- Rich Ulrich, [EMAIL PROTECTED] http://www.pitt.edu/~wpilib/index.html ================================================================= Instructions for joining and leaving this list and remarks about the problem of INAPPROPRIATE MESSAGES are available at http://jse.stat.ncsu.edu/ =================================================================
