Thursday, May 10, 2007

Review & Prepare!

Here are some sites that I've found with info on micro in general, studying for the AP, tips, tricks, hints, and things that people commonly mess up on. If you've found anything else, post in a comment so others can visit them, too! :) Let the linkfest begin!

General Stuff:

Some adventurous teacher/AP grader put together info on some of the most common mistakes that students make on the national exam that cost them points. Yeah, it's 108 slides, but you could hit some of it to get some ideas, and there's a kind of "table of contents" on the left side: mhtml:!COMMONMISTAKESONTHEAPMICROEXAM_files/frame.htm

AMOSweb, searchable economics database:

Online m/c test for practice:

And the answers:

QUIZtastic on AMOSweb (they capitalize stuff weird) - practice quizzes:

Interactive tutorials:

College level - online info with quizzes, tutorials, lecture notes, etc - loads of great stuff:

Online econ textbooks:

The online economics text that I borrow the animated gif files from - they're all here!

All the graphs you "need" to know, animated gif files, VERY GOOD INFO HERE!
Okay - Basic Concepts:
Micro Graphs, Part I (S & D through PComp):
Micro Graphs, Part II (Mon. through income distrib.):
World Price & Tariff Graphs:

Economics at - lots of info, lots of links, could help with application:

McConnell & Brue textbook site - this is the most often used text for AP Econ, and it has all kinds of info online. If you're not understanding something in Mankiw or McEachern, try here. Plus there's outlines, quizzes, etc.

Book outline notes, but check for micro vs. macro. It's not showing up on this screen, and it's been awhile since I looked at it. Stupid ALC computer. :)

Online quiz sites:

Other Blogs:

These could help with application and general knowledge. Since blogs are constantly changing, I have no specifics on here, but there's a ton of info. Really. <--This is the blog of the guy who wrote our text. :)


Wojtek said...
This comment has been removed by the author.
Wojtek said...

thats the link to the presentation with 108 slides. Its better to download it straigt from that site, rather than opening in the browser from the link.

domino said...

can we please review elasticity in class? everytime i try to review it on my own i end up more confused and i consistently get those questions wrong on the tests.


Wojtek said...

aaa forget what I said before. you cant download this presentatnion. I don't have enough patience to wait till it opens- good luck :)

KM said...

Sure, Domino - we can do elasticity on Monday or Tuesday. Remind me if I forget. :)

Gina said...

What is the difference between a natural and a single-price monopoly? When asked a question about a specific kind of monopoly, will or when will it affect the answer? Or can I just think about a monopoly in general?

Ashley said...

This website is set up by a teacher i believe. If you scroll down to the end of the page you will see each chapter they covered and what the chapter was on. If you click on red "single document html format" it gives ALL the notes for that chapter.

Ashley said...

Ok and whats the difference between perfectly elastic and unit elastic, and then perfectly inelastic and unit inelastic?? i skimmed through my notes and i think that actually confused me more! But maybe thats what Domino was talking about too.

Ashley said...

Ok, one more comment: natural monopolies are normally regulated right? Are they always in an economy of scale?

KM said...


A natural monopoly is just a type of monopoly that is allowed by the government to continue. For some reason, they have a monopoly on a good or service for a very good reason - they are the only ones that laid the cable line, for example (or the phone lines, or the water pipes, etc). Since they own the lines, they aren't going to let someone else come in and use their lines as competition against them. Although they're regulated by the government (Ashley's question), the government for the most part lets them be - so therefore, we get the big cable prices, etc. Natural monopolies will always produce in the economy of scale because otherwise they will not see a profit and will close or jack up prices.

A single-price monopoly is just assuming that they are not price discriminating - so, they are acting like we talked about in class, choosing to set a price depending on their own costs & benefits and the demand for their product.

In a FRQ, assume it is a normal, single-price monopoly like we analyzed in class. If they want some other info, they will tell you. A natural monopoly can be/will be a single-price monopoly.


Elasticity - in general terms, it's how much quantity demand changes with any change in price.

If QD changes a lot with even a little change in price, it's more elastic. So - if the price of gas rises from $3.19 (price here in Milton today...ugh...) to $5.67 a gallon tomorrow morning, people will change (probably) how much they drive. It's changing how much you're willing to buy. So with that price change, it is elastice. A perfectly elastic good has a perfectly horizontal demand curve (think "E" on the graph) - even tiny changes in price will change the quantity.

On the other hand, an inelastic good means that there are some items that - no matter what happens to price, you still have to have it. For most people, if gas was $2.90 two weeks ago, but is $3.19 today, that's not enough of a change to actually change driving habits. Or, medicine that you need to live. Or, things that are vitally important to YOU. So - elasticity can be very personal. But - something that is perfectly inelastic means that no matter what happens to price, people will buy the same quantity - so it has a perfectly vertical demand curve ("I").

Unit elastic is the perfect curve - as there is one unit of change on the price axis, there is one unit of change on the quantity axis. I wouldn't use the term "unit inelastic" - it is inaccurate.

One last part - as you move along any demand curve, no matter the slope, the elasticity will change because of the way elasticity is computed. Slope does not equal elasticity. Because elasticity is determined by % change in QD/% change in price, as you go along the D curve, those percentages are different. Remember the longer value of the equation: Q1-Q2/(Q1+Q2)/2//P1-P2/(P1+P2)/2 where // = the big division. If that makes any sense. :) So - if you are looking at higher prices and lower quantities, the elasticity will compute differently than when you look at lower prices and higher quantities. Just try the math sometime.

Kate said...

so i was looking over the test and i was confused by something. why if something is a negative externality do we make more of it? i can't figure that one out.

KM said...

If something is a negative externality, the original equilibrium point (where the true cost = demand) is at a lower price but a higher quantity than the true externality price (where the marginal social cost = demand).

Think of it the original equilibrium point is where we're at, really. But when you add in the social costs (which may or may not really be money, it might just be OC, like cancer or something like that, which is caused by the externality), it makes it more expensive.

So, that shift creates the "new" equilibrium point where MSC = D. At that point, the price is actually higher because it's taking into account how much "bad" that externality is causing.

Does that make sense?

D Mac said...

i found this, its pretty good as far as bein able to apply stuff and it has an econ glossary on the page.

D Mac said...

so, i thought i got nash equilibrium and prisoners dilemma pretty solidly when we did it in class, but according to the last test i'm kinda confused. looking over my notes again i see what i did wrong with the prisoners dilemma, but still don't understand where i went wrong on nash equilibrium, so i was just wondering if there was an easy way to remember what the nash equilibrium is all about.

KM said...

Nash: think of it like this -

You pick what is best for you, regardless of what the others do.

Or - if everyone in the game chooses a solution, and then you tell everyone involved in the game what each others' solutions are, and no one changes their mind - then, you have a Nash equilibrium.

Jason Welker said...

Hi KM. I am an AP Econ teacher too, and found your blog while doing a little research. I was wondering if you'd mind me adding a link to your blog on my own blog site ( It looks like students are very involved with your blog, which is cool. I've just been blogging and using wikis for a few months, but have found students to be very receptive. Let me know if I can post a link to your blog from my own, so that my students here in Shanghai can benefit from your insights and views. Thanks. Jason Welker - Shanghai American School

D Mac said...

so then, in the prisoners' dilemma would the equilibrium be both confessing or both staying silent? because the best course of action is to confess, but if you could inform each person as to what the other is doing, it would be to stay silent. thats kinda where i get confused.

KM said...

Both confessing - because that is your best choice regardless of what the other is doing.

Wow...a note from a school in Shanghai. How cool! :)

Reff said...


Thank you for sharing many of the lessons that Dick Brunelle and I created at

Keep up the GREAT work in spreading the word of economics to others !!!!

Hope everyone did well on the AP Economics exam on Thursday, May 16, 2007!

As always, live well,laugh often, and love life much,