Ironworks Trivia Contest

[Aelia Jusa]

Geez! These ones were hard! Ah well, I did win yesterday, woo! LOL Jorath s.m.r.t...

[Azred]

The probabilities of getting n questions correct by guessing (p(correct) = 0.25):

n.....p (in %)...cumulative p (n or fewer questions correct by guessing)
0.....5.63.......5.63
1.....18.77......24.40
2.....28.16......52.56
3.....25.03......77.59
4.....14.60......92.19
5.....5.84.......98.03
6.....1.62.......99.65
7.....0.31.......99.96
8.....0.0369.....99.9969
9.....0.003......99.9999
10....0.0001.....100

Thus, if you guess 5 or more correctly you're doing really, really well. [img]graemlins/petard.gif[/img]

[ 09-08-2005, 04:56 PM: Message edited by: Azred ]

[Sir Goulum]

Heck, with my luck, I'd be good to get 1 right. [img]tongue.gif[/img]

[Ilander]

I got 1 right!

Man, I think my scores here and at the Oasis game are inversely proportional.

[Sever]

Originally posted by Azred: The probabilities of getting n questions correct by guessing (p(correct) = 0.25): n.....p (in %)...cumulative p (n or fewer questions correct by guessing) 0.....5.63.......5.63 1.....18.77......24.40 2.....28.16......52.56 3.....25.03......77.59 4.....14.60......92.19 5.....5.84.......98.03 6.....1.62.......99.65 7.....0.31.......99.96 8.....0.0369.....99.9969 9.....0.003......99.9999 10....0.0001.....100 Thus, if you guess 5 or more correctly you're doing really, really well. [img]graemlins/petard.gif[/img]

Ok, i'm getting off topic a little here, but i need you to explain the maths you're using here. I learned this in dummy mathematics in year 11 but have since forgotten. And unlike other math, i actually have a use for this...

The example given to me back then was the probability of having 12 children and all of them being female (which is, i think, a current guiness record). I tried to explain this near impossible probabilty to a friend but choked badly. He insisted that it was still 50%. Care to explain, in dummy terms mind, how to work it out? [img]smile.gif[/img]

[Aelia Jusa]

Isn't it that the chance of having 12 babies all being female is very small, but if you have 11 girls then the chance that your next one will be female is still 50% because probability has no memory? Like, if you toss a coin whether heads or tails comes up has no bearing on whether you tossed heads the last time you tossed it. Or something? [img]graemlins/blush.gif[/img]

[Azred]

Combinations. Suppose you have k objects and you want to arrange n of them, the formula is kCn = k!/(n!*(k-n)!) Example: 10C5 = 10!/(5!*5!) = 252.

The probability of answering correctly with a guess is .25; hence, the probability of guessing incorrectly is .75. If you guess 3 correctly that means 7 incorrectly, or (.25^3) * (.75^7). Since each question is independent, you wind up multiplying the probabilities together.

Getting three questions correct means arranging 3 out of 10. From the above forumla, 10C3 = 10!/(3! * 7!) = 120 ways of answering 3 correctly.

Putting the forumulas together gives...
...the likelihood of answering n questions correctly = 10Cn * (.25^n) * (.75^(10-n)). For 3 questions 120 * .25^3 * .75^7 = .250282288.

For the cumulative probabilities, obviously add.

Simple, yes? [img]graemlins/petard.gif[/img] Now, if only I could answer some of those ridiculous questions. [img]graemlins/laugh3.gif[/img]

[Azred]

No, I got 2 correct, which is about usual for me when it comes to minute details of Australian town locations, the history of Finland, and more Australian sports.

It says "all world", but a majority of the questions are Australian. Oh, well. [img]graemlins/petard.gif[/img]

I just decided to change my strategy here. Since I don't know the answers anyway, I'll just pick random choices and submit my answers within 20 seconds. What I miss in accuracy I'll get back in speed. [img]tongue.gif[/img]

[ 09-09-2005, 07:19 PM: Message edited by: Azred ]

[Sir Goulum]

I get loads of british and european questions, not so much australian anymore.

[Aelia Jusa]

Could we maybe change the topic for a bit? Maybe we could have a week with films/literature/sports/etc - a different one each day or couple of days. I'm personally getting a bit sick of world knowledge, especially since I have to guess most of them (which I think is true of most of us!). Yesterday I got at least 4 about Denmark!