Probability Question.

[pyrate83]

Ok, I'm not trying to get anyone to do my work for my statistics class but I'm having trouble figuring/understanding how to figure probability out.
The problem states: the max score possible on the SAT is 1600. According to the test developers, the chance that a student scores a perfect 1600 on the SAT is 5 in 10,000.

It wants to know what the probability that a randomly selected student scores a 1600 on the SAT.

This is the only problem I'm really stuck on and any help would be appreciated.
Thanks.

[northcat_8]

Oh man...statistics I hated statistics...

...now I had better disclaim this before hand...

I'm a few glasses of Jack and abotu 4 beers in...so this may not be entirely accurate

But as of now I would think that you just put 5/10,000 and reduce it. 1/2000.

I may review this post in the morning when I'm a little more clear minded.

Probability is the number of favorable or desired outcomes divided by the total number of possible outcomes.

[pyrate83]

Ok, well that's what I did but I was just checking because it seemed a bit too easy.

[MackemX]

yep 2000-1 are the odds or a 0.05% chance

[northcat_8]

I maybe a lot drunk but odds and probability are 2 different things.

Probability is the number of favorable or desired outcomes divided by the total number of possible outcomes.

Odds are the number of favorable outcomes divided by the number of unfavorable outcomes.

Example: 3 blue marbles, 4 red marbles.

Probability of pulling out a blue one is 3/7.
The odds of pulling out a blue one is 3/4.

<anyone else notice how many times you use the backspace key when drinking while posting?>

[MackemX]

odds are the unfavourable/favourable aren't they?

as in you have a 2000/1 chance or a 1 in 2000 chance

, I'm confused now

[pyrate83]

Damn, I get so confused with my statistics class too. I hope this is the only time I have to take it.

[northcat_8]

odds are the unfavourable/favourable aren't they?

as in you have a 2000/1 chance or a 1 in 2000 chance

, I'm confused now

Hmmm...I think when talking odds you are always comparing. Like in my example, your odds of pulling blue marble would be 3/4 but the odds of pulling a red would be 4/3.

I think I've a few to many to figure it out tonight....not like it's really that important anyway I'm sure it's in one of my books somewhere, I'll look it up tomorrow...

[pacmania_2001]

Ahhh Statistics, I don't normally swear but I ******* hated that class at university.

Luckily I got a conceded pass so I'll never have to consider things like standard deviations again.

[pyrate83]

Ahhh Statistics, I don't normally swear but I ******* hated that class at university.

Luckily I got a conceded pass so I'll never have to consider things like standard deviations again.

How the hell did ya pull that one off pac?

[pacmania_2001]

Alot of luck and bullshiting.

In the final exam which is 2 hours long I left after 45 minutes. I guessed probably half of the multiple choice questions (always go for C) and for the long answer questions I used what I like to call "voodoo maths". That basically means I scribble whatever random bits of information I could remember that are relevant for the course into the answer space and hope that I can get a few marks here and there.

My mates aren't too happy. All of them got a 2 (fail) whilst I got the 3 (conceded pass) so I don't have to do it again whilst they do.

[pyrate83]

Alot of luck and bullshiting.

In the final exam which is 2 hours long I left after 45 minutes. I guessed probably half of the multiple choice questions (always go for C) and for the long answer questions I used what I like to call "voodoo maths". That basically means I scribble whatever random bits of information I could remember that are relevant for the course into the answer space and hope that I can get a few marks here and there.

My mates aren't too happy. All of them got a 2 (fail) whilst I got the 3 (conceded pass) so I don't have to do it again whilst they do.

Nice. I wonder what the probability of guessing a C for multiple choice questions and getting it right is...oohh my head hurts.

[pacmania_2001]

In my experience if you answer C for every multiple choice question you get about 33%.

[pyrate83]

I see.

[pacmania_2001]

Thats in my experience of course.

I remember my sociology teacher explaining one day why C occurs more in MCQ tests when the test is designed by a human but for the life of me can't remember the reason he gave.

In a computer test its random though.

[offline]

Even with SPSS, statistics is the worst subject
on earth. It is the only subject that has consistently
held me back - even if I get a credit.

[Craig Tucker]

We have the occasional multiple choice test here, but if you get it wrong you are deducted a mark. Eliminates guesswork, you are better of not answering the question than guessing.

[Cobra]

I hate statistics. I use MiniTab to do it for me, but making sense of the results it spews out is quite a task sometimes.

[Craig Tucker]

I did statistics in my final year, most boring subject ever. And the lecturers droning voice did not help. Only 2 of us passed on the original marking, so they were remarked to increase the pass rate.

[northcat_8]

In my experience if you answer C for every multiple choice question you get about 33%.

Well that's good then. Considering that if you have 4 choices, the probability of "C" being the correct answer would be 25%

[pacmania_2001]

In my experience if you answer C for every multiple choice question you get about 33%.

Well that's good then. Considering that if you have 4 choices, the probability of "C" being the correct answer would be 25%

In theory it should be 25%. In practice every test I can remember doing though has a higher percentage of C than any of the other four choices.

[ViRaL1]

Does it not give you the number of students?

[pyrate83]

Does it not give you the number of students?

If you're referring to my question the number of students is 10,000.

[ViRaL1]

If that's all the info they gave you, that doesn't really sound like much of a statistics problem. If that's all there is to it, they're outright giving you the answer. Although it helps to reduce the fraction to 1 in 2,000, technically I believe 5 in 10,000 is still correct. If they gave you some number of students other than 10,000 that might make it something to figure out. It just seems to me like something it missing, but if that's all there is then that's all there is.

[yoda313]

Hello,

BASE TEN is all I have to say...

Kevin

(northcat and a few others might recognize that from awhile back..... )

[pyrate83]

If that's all the info they gave you, that doesn't really sound like much of a statistics problem. If that's all there is to it, they're outright giving you the answer. Although it helps to reduce the fraction to 1 in 2,000, technically I believe 5 in 10,000 is still correct. If they gave you some number of students other than 10,000 that might make it something to figure out. It just seems to me like something it missing, but if that's all there is then that's all there is.

Yeah that was all there was. I was surprised too. The second part of the problem was like in a more recent study 545 students got a 1600 on the SAT. Given the probability from the previous question, how is this possible? That one made me think a little more.

[ZAPPER]

About the multiple guess test. In high scholl I had a cool chemestry teacher. He was big into random as being the fair way to do things. Each desk was assigned a card name from a regular poker deck. When it was time to give an answer or go to the board and do a problem he would pull a card from the deck and whoever was in that seat was the victom.
On multiple choice test he randomly picked the position of the correct answer A,B,C,D and built the test around that. The kick in the ass was what he called the monkey test. He would again randomly pick the answers to a test and then score it. At the end of the year if you just showed up every day and randomly took the test you were supposed to be able to pass. The monkey for our class got a "B" I don't remember all of the details now but he recorded every result of every draw for every class. He put a heavy load on attendence and we argued about that not being a fair measure of what we learned. But his logic was that as long as we were in his room, we would learn something about chemestry. He kept it interesting enough that sure as hell even fellow students that had trouble in their other classes did well in his.

[offline]

Well I had a uni multiple choice
test where the structure was either:

a) a
b) b
c) c
d) a & c
e) b & a
d) all of the above
e) the question is invalid / cannot be answered
f) other. please specify _____

No I'm not making this up. It was a nightmare

[Craig Tucker]

So in the space for question f, what do you put "g"

[pacmania_2001]

We get alot of those in our university tests.

a) X
b) Y
c) Z
d) X and Y
e) X and Z
f) None of the above.