Solutions to Homework 6

I'm sorry it took so long to post the solutions to Homework 6 that is due at the test on Monday.

I was out of town and my internet connection was terrible. I finally was able to post it at 1:30 a.m. Monday. I hope you are able to look it over so that you can review it before the test.

Again, I apologize for the delay. The calculations are rather detailed so it should help you see the calculations.

It is posted on the I-drive.

Please remember it is due at the test. Make sure you bring it to the test with you. I know you have the answers. Since the answers have been posted I will ONLY accept the homework at the test.

JJ

Answer key to sample problems for test 2

Here is the answer key for the sample problems. I confess that I put it together very quickly and there may be a few errors. Please let me know if you think any of these is incorrect. Also, make sure you check back later for any updates or corrections.

1-A, 2-C, 3-B, 4-C,
5-D, 6-D, 7-B, 8-D, 9-B, 10-C, 11-A,
12-A, 13-B, 14-D, 15-A, 16-C, 17-D, 18-A,
19-C, 20-B, 21-A, 22-B, 23-E, 24-B,
25-A, 26-B, 27-C, 28-C, 29-E,
30-D, 31-C, 32-D, 33-A, 34-C, 35-D, 36-C, 37-A,
38-D, 39-B, 40-A, 41-B, 42-B.

Prof. Jack Julian’s Revised Office Hours Week of October 19, 2009

Monday, October 19, 2009

11:00 a.m. – 12:00 noon

Tuesday, October 20, 2009

12:45 – 1:45 p.m.
3:15 – 4:15 p.m.

Wednesday, October 21, 2009

11:00 a.m. – 1:00 p.m.

Thursday, October 22, 2009

No Office Hours

Friday, October 23, 2009

No Office Hours

Test 1 scores and scale

This is not a posting of scores but a posting of the distribution of scores and an approximate grade scale. (Please note: there is NO letter grade recorded for the test, only your raw score which is appropriately weighted is entered into the grade book. Hence, in the future it is NOT appropriate to ever say to me "I got an A on the first test and a B on the second, what do I need to do to get an A in the class." You get points. Points are what matter. The reason I give the scale is for you to know if you are doing "high quality" or "poor quality" work both overall and within a targeted grade range.

First, some descriptive statistics:

Average score is 34.70 (out of 45), or about 77.1%
Median score is 35.25, or about 78%

The mean and median are pretty close together, which they should be. The average is slightly below my target of 80%, but not that bad.

A measure of "dispersion" is the standard deviation. My target is 10%. This test had a standard deviation of 5.44 points or approximately 12.1%. This is a wider than expected dispersion. Another statistic, skewness, is "negative" which suggests that there were a few pretty low scores that made that standard deviation a bit high.

So, there is the approximate grade scale (to be interpreted as relative quality of work). In terms of the raw score,

A: 40 and higher (freq: 20)
B: 34.5 - 39.5 (freq: 34)
C: 29.5 - 34.0 (freq: 26)
D: 24 - 29 (freq: 13)
F: 23 and lower (freq: 3)

(freq is "frequency" which is the number of observations in that range. Note that there are more As and Bs total than Cs, Ds, and Fs.)

Overall, I think it was a good test of reasonable difficulty. Keep up the good work.

Be nice to me

Uh, I've gotten a few emails because of a few errors in my posting of the answer key. Please keep in mind I'm doing a special service here. I appreciate you using a much more civil and respectful tone, even when I make a mistake. If you guys lapse into talking to me like I'm a pal or a dumbass I'll cut these modes of communication and make you come to my office.

As a prof, I think you should speak to me as if you are talking to a guy who has the power to hire and fire you.

Thank you for your understanding.

Review info: oops

I apparently did not post the review sheet (that I handed out in class) onto the I-drive. I know a few people didn't get it. If anyone is able to scan it and send me a copy, I'll post it onto the I-drive. (Please submit as one four-page pdf if you are able, but jpgs would be ok.) My copy is at the office and I'm not able to access it until I get back to the office Monday morning.

A few of your classmates may thank you. (I will give you public thanks on the posting as being one of the coolest people in class.)

JJ

Answer Key to sample m.c. problems for test 1

Here is an attempt at the key. Let me know if you think any of these is wrong.

1-A, 2-A, 3-B, 4-A, 5-C, 6-A,
7-B, 8-D, 9-C, 10-C, 11-A, 12-C, 13-B,
14-B (originally marked C), 15-D, 16-B, 17-B, 18-A, 19-A,
20-D, 21-C, 22-B, 23-B, 24-C, 25-B, 26-C,
27-B, 28-A, 29-C (originally marked B), 30-A, 31-A,
32-A, 33-D, 34-C, 35-D, 36-A, 37-B,
38-D, 39-D, 40-B, 41-A,
42-C, 43-B, 44-B, 45-C, 46-C, 47-C, 48-A (originally marked B),
49-C, 50-A, 51-B, 52-A, 53-D,
54-A, 55-D, 56-D, 57-B, 58-C.

If you have a comment, I may be slower seeing a posting rather than an IM or email (preferred).