Little help with some math?

[Douglas]

Originally Posted by rdawson808

Unless I'm missing something, he can't know this. This hinges on him wanting no risk.

As I read it, another way to state his question is "how many of the terms do I need to study to guarantee that I have studied the ones that will be asked?" (I'm ignoring the word "particularly" because it is undefined.) The inherent problem is that he has zero knowledge of which ones the prof will choose. So each has equal probability of showing up. And that probability is positive. Therefore he must study each.

But I'm no probability expert. I could be missing something.

21 is correct. Let's assume he studies just 21, which leaves 6 unstudied. So in the worst possible scenario for him, all 6 unstudied questions appear on the exam. The chances of that are miniscule, but that's the very worst he can do. That means he'll still know 3 of the 9 questions, which he can answer, and he'll be fine. There is no risk that he won't know at least 3.

 

[imageWIS]

Originally Posted by Douglas

This is a trick question. He will actually have to study 42.

OMG, I hate probabilities. I know they are very useful, but nonetheless I hated studying the math for QMB class.

 

[Flambeur]

21 = riskless goddamnit. This isn't tough, even for someone who hates math like I do.

 

[ozymandias]

Thanks a lot guys, 21 makes sense. Almost all of my political science exams are structured this way. We answer a few paragraphs defining 3-4 terms out of a larger list we are given prior. Something tells me the only reason he does that is so he can make a joke every time that since we live in a liberal democracy we must have choice.

 

[rdawson808]

Originally Posted by Douglas

21 is correct. Let's assume he studies just 21, which leaves 6 unstudied. So in the worst possible scenario for him, all 6 unstudied questions appear on the exam. The chances of that are miniscule, but that's the very worst he can do. That means he'll still know 3 of the 9 questions, which he can answer, and he'll be fine. There is no risk that he won't know at least 3.

gotcha. i see now.

 

[gsugsu]

So how hard is it to study for the 27 terms? Do you have an inordinate amount of other exams or work that you are facing that you which forces you to spot study or is this about laziness?

 

[Douglas]

Originally Posted by gsugsu

So how hard is it to study for the 27 terms? Do you have an inordinate amount of other exams or work that you are facing that you which forces you to spot study or is this about laziness?

What are you doing posting on this website? Don't you have some work you could be doing or is this about laziness?

 

[VKK3450]

Not actually the OPs question, but what is more relevant is the pass mark.

See, we are assuming that he needs to answer all 3 correct, when in reality the pass mark could be 60% in which case correctly answering 2 of the 3 would be enough, leaving the answer at 20.

K

 

[rdawson808]

Originally Posted by VKK3450

Not actually the OPs question, but what is more relevant is the pass mark.

See, we are assuming that he needs to answer all 3 correct, when in reality the pass mark could be 60% in which case correctly answering 2 of the 3 would be enough, leaving the answer at 20.

K

As a former college professor (who never taught stats or probability), can I plead that we not encourage the OP to study as little as possible? Ugh. Lazy students.

Although, I was thinking the same thing earlier (if he gets those two 100% correct).

b

 

[VKK3450]

Originally Posted by rdawson808

As a former college professor (who never taught stats or probability), can I plead that we not encourage the OP to study as little as possible? Ugh. Lazy students.

Although, I was thinking the same thing earlier (if he gets those two 100% correct).

b

I almost skipped one of my final assignments because I figured that based upon my current grade and the % weight, I could afford to get a 0 and still pass (pass / fail course).

My advisor did not like the idea and insisted that I submit something that at least looked like I made an effort.

K

 

[EL72]

Originally Posted by rdawson808

As a former college professor (who never taught stats or probability), can I plead that we not encourage the OP to study as little as possible? Ugh. Lazy students.

Although, I was thinking the same thing earlier (if he gets those two 100% correct).

b

Since you taught econ, you should appreciate that studying 21/27 is not an issue of laziness but of utilty maximization. As a professor, I can totally understand this reasoning. If I was concerned that students would not study in a sufficiently comprehensive manner, I would not structure exams this way (which I don't) but I cannot fault students for understanding the basic rules and working accordingly.

And to the OP: it does worry me a bit that you are in college and need to ask this question on a message board. This is basic arithmetic and not even a remotely complicated probability computation.

 

[mondayc]

You paid to learn all 27, but only need to learn 21. The minimum got me through public school with A's, but when you're paying for college it's sort of stupid to not learn as much as you can.

 

[rdawson808]

Originally Posted by EL72

Since you taught econ, you should appreciate that studying 21/27 is not an issue of laziness but of utilty maximization.

This only holds true if the marginal value of the additional knowledge is less than the cost of obtaining it. I found that students oftentimes undervalued what was being taught (be it econ or art history) and therefore sought to minimize their costs (effort) needed to gain a certain amount of knowledge. But they chose that level of knowledge (21 out of 27 terms) due to their myopia.

The easiest example of this to grasp would be if the OP is dealing with a midterm. What if those other six terms are also necessary for the final? It could be too late to also learn those at the end of the semester due to the amount of material he needs to ingest. And this of course ignores the long-term value of the knowledge, which is probably very hard to measure.

b

 

[ozymandias]

I'm all about maximizing the material I can learn, but sometimes it's just not an option. While I try to look at everything the prof. mentions it's unrealistic to study all of it. And besides preparing for the 21 means structuring my answers, writing out topic sentences and rounding up relevant evidence. It's a tad different from simply reading all parts of the reading material.

 

[clee1982]

21