Statistics 11/Economics 40 Midterm 1 Results

Mean =51 or 68%

Standard Deviation =14.5

Median =55

High =75 (1)

Low =18 (1)

There were 3 forms and no statistically significant differences in the average scores between forms.

Keys have been posted to the web, please see your TAs or me for exact solutions or help with solutions.

Again, some of you found this test easy, others found it very difficult. The most difficult problem appeared to involve the "portfolio of 9". The trick to doing that one correct was to realize that while both involved samples of size nine, each question asked for a different thing. One asked about the distribution of the mean of 9 stocks, the second asked for the probability that for the sample of 9, all 9 stocks would be greater than some amount. The funds were normally distributed and you could use the properties of the normal to help you estimate probabilities in either situation.

This is how you should think about your grade on the second midterm:

"A grade" 64-75

"B grade" 51-63

"C grade" 39-50

below a 39 is a "did not pass"

This is very premature and does not include homework scores or lab scores and there is still a final worth as much as both midterms combined and it assumes that no one improves or does worse on the final and I'm being conservative here in the hopes of not raising your expectations unreasonably. But this gives you some idea of where you stand after two midterms, (these are total points 120 possible: 45+75):

"probably an A" 110-120

"probably an A-" 100-109

"probably a B+" 96-99

"probably a B" 87-95

"probably a B-" 80-86

"probably a C+" 71-79

"probably a C" 51-70

"probably won't pass" below 51

Please make an effort to see me or talk to your TA if you are not passing the course but are planning to stay enrolled. We will do our best to help you figure out how best to study and to clear up any specific problems you are having with the material. Failing after two midterms does not necessarily mean you will fail the course, but you should be concerned. Again, please remember that grades are not assigned yet, but I am trying to give you guidance as to where you stand with respect to your classmates.

The course is graded on a "curve".

If you plan to contest your examination grade, please read the instructions found in the syllabus. You have 3 working days, (this means by March 8, 2001) to submit a challenge in writing. E-mail is considered "in writing".