Ooops (Homework 7)

Problem number 3 on Homework 7 is the same as problem 2 on Homework 6.

You DO NOT have to do it again. Just do the first two problems.

J

a piece of advice

Looking over the last homework I have some things to say:

You should take these, and any assignment, as an opportunity to display acquired knowledge and understanding. Take pride in your work. Show off how thorough your effort is.

The presentation of even the most mundane calculations or diagrams or arguments should be presented in a clear, legible manner. Ripped and torn sheets and hand scribble would generally be frowned upon by an employer.

My request for brevity does not mean you ought to sacrifice information. Again, please be thorough.

Tutoring cancelled

I regret to inform you that the peer tutoring that was available on Wednesday evenings at Pratt Hall will no longer take place. We will probably not have another tutor for the rest of the semester. In the event that we are able to come up with an alternative you will be informed. Otherwise, it looks like your struggles with the material and homework problems should be directed to the instructor.

J

"Grade" distribution of Test 1

Your reported score is a raw score out of 40 possible points. You can turn that into a more familiar percentage score by

your score
---------- x 100
40

Here are some descriptive statistics which are used to determine the grade scale:

average = 29.2 out of 40, or approximately 72.8%
median = 29 (this is the "middle" score if we ranked all scores)
mode = 33 (this is the most frequently occuring value. there were four 32s)

All of the above help determine the "middle". For this, I think the mode is not a good middle. But I think 29 is a good middle. That score, then, is the lowest B.

The standard deviation can be used to measure the distribution of scores around the mean. I like to target 10%. The standard deviation for this test was 4.2 out of 40 or about 10.4%. Pretty close.

So here's a grade you can associate with your score:

A range: 33 and higher
B range: 29 - 32.5
C range: 25 - 28.5
D range: 20 - 24.5
F range: 19.5 and lower

Be aware: I do not enter a letter grade into my gradebook for any assignment. I enter only your raw score. It is appropriately weighted given point value of the assignment (40 points in this case) and the weighting value as expressed on the syllabus (15%). So, using measured language here, if you got the score of 26.5 you received a B-type grade. However, you did not "get a B" because that letter isn't recorded. What ultimately matters is the weighted average of all assignments at the end of the term.

After the second test and the mid term grades are determined I will carefully go over the weighted average calculations. It is fair that you know your overall standing in the class after each exam. Given the number of assignments so far, this test is your first measure of "expected grade".

Answer Key to Sample MC questions for Test !

*** OFFICE HOURS ALERT ***

I will be out of the office as of 11:15 a.m. on Thursday, February 8 (and not return until Monday morning). I am unable to hold office hours on Thursday from 11:30 to 12:30. You should be able to find me in the office that morning from 9:00 - 9:45. I will also be in the office Wednesday 4 - 5 p.m.

I will be online with my AIM on Wednesday evening after 8 p.m. until I fall asleep.

I'm sorry for any inconvenience this might cause.

*** END ALERT ***

Here is the key to the sample test and a few comments below.

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



On 3: goods are scarce in supply, but we would not call them resources

On 7: Trade between countries is based on the same principle as trade among individuals: exploiting different opportunity costs.

On 8: I did not discuss this in class but it should be clear from the readings. In a nutshell: Positive economics seeks to explain economic phenomena and to draw inferences based on these relationships (e.g., the price is $5, or if the supply decreases we can expect higher prices and lower quantities). However, values, morals, and other personal preferences can come into play, often in policy situations. (Taxes on cigarettes should be raised. We should build a highway directly from Pittsburgh to Indiana. We should subsidize farmers.) In class, we aim to be positive.

On 12: The production of football helments decreases at an increasing rate. But given that is not an alternative, decreasing would be the answer. But decreasing at an decreasing rate means "decreasing opportunity cost".

On 22: Keep in mind, demand curves slope down

On 24: B is not true because as the price of getwids decreases, there is an increase in quantity demanded--but not an increase in demand.

Changes in demand are when the demand curve shifts. Changes in quantities demanded are due to changes in the price of the good. Since price is on the vertical axis, we merely find movement along the existing demand curve.

On 31: Sorry, that is a tough one.

Tutoring

At the end of class on Tuesday I mentioned that a tutor was available in 212 Pratt Hall on Wednesdays, 7-9 p.m.

HOWEVER, the tutor is NOT available this Wednesday, so there will be NO tutoring this Wednesday, February 7.

Sorry.