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# s2 OCR how did u find it?? watch

1. (Original post by ZoGgEr!)
lol, reading threads like this gets so frustrating, there's nothing you can do about it now anyway... I was happier about the exam before I started reading this thread... Always something little to take away from the marks...

I got something like 0.002 on the type II error, btw, but I can't remember the methods...
omg so true before reading this thread i thought i had caned the paper but now im doubting myself on a few stuff!!!!!! yeh every1 else seems to hav got a really big number for the type II error but i got a really small number like u... 0.0445 or sumthing im not sure. tho that may hav been an answer to another question...
wasnt type II if u accept Ho in which case it wud be greater than 3 or watever it was oh u no wat im not gna stress myself out over this.

ill jus leave this thread now telling myself it went amazingly!...

oh yeh and it was to accept H0 in the last question and the other question was binomial to poisson. i am 100% sure on this!
2. Type 1 = (reject H0/H0 is true)
type 2 = (accept H0/H0 is false)
3. Hey - just wanderin if any1 has a copy of the paper? I wanna see the poisson approx or was it binomial... question again!?
4. blah how annoying that the last question was just 2tailed. I just read it and thought hmm o one of those 'music helps you concentrate' types of tests so obviously its just one tailed... silly silly me
5. (Original post by Bhaal85)
Type 1 = (reject H0/H0 is true)
type 2 = (accept H0/H0 is false)
Other way round. The probability of accepting Ho when Ho is false is the significant level (critical region) which is Type 1.

Checked textbook too, to make sure
6. (Original post by Urdegish)
Other way round. The probability of accepting Ho when Ho is false is the significant level (critical region) which is Type 1.

Checked textbook too, to make sure
How sure are you? because I'm pretty damn sure that it it definetly
P(Type I) = reject Ho when Ho is true
P(type II) = accept Ho when Ho is false

your explanation ofthe significance level also does not make sense. The type I error is the same as the significance level, which in this case is 5%. therefore there is a 5% chance of rejecting Ho when Ho is true. I would check your textbook personally
7. (Original post by sioniebaby)
How sure are you? because I'm pretty damn sure that it it definetly
P(Type I) = reject Ho when Ho is true
P(type II) = accept Ho when Ho is false

your explanation ofthe significance level also does not make sense. The type I error is the same as the significance level, which in this case is 5%. therefore there is a 5% chance of rejecting Ho when Ho is true. I would check your textbook personally

For a binomial/possion the actual value found will be the significance level, for a countinous distributions like the normal, the significance level is the actual significance level given.
8. OMG....
that paper was fairly easy....

E(t) was 12... correct

The last question was a two tail..... critical region was 1.96 and the answer comes out as 1.7... so therefore Ho is accepted, music dont help ya one bit.. ( we all know thats lies)

The only one i found hard was the fish distrobution one, when you end up getting a binomial of (50,0.0231) (not sure on the correct figures)... anyone just use the binomial expansion for P(X>2).. using 1-P(X<=2)????

the rest of my year used poison again... but i just used the binomial thing......

Hope they allow that, else its 4 marks lost..
9. (Original post by tommyg)
OMG....
that paper was fairly easy....

E(t) was 12... correct

The last question was a two tail..... critical region was 1.96 and the answer comes out as 1.7... so therefore Ho is accepted, music dont help ya one bit.. ( we all know thats lies)

The only one i found hard was the fish distrobution one, when you end up getting a binomial of (50,0.0231) (not sure on the correct figures)... anyone just use the binomial expansion for P(X>2).. using 1-P(X<=2)????

the rest of my year used poison again... but i just used the binomial thing......

Hope they allow that, else its 4 marks lost..
I know a few people who just stuck with the binomial, although I used a poisson since the question asked for an approximation, and the only approximation for X~B(50, 0.021) is X~Po(1.05)
10. (Original post by abc123)
I know a few people who just stuck with the binomial, although I used a poisson since the question asked for an approximation, and the only approximation for X~B(50, 0.021) is X~Po(1.05)
Its getting repetitive, it's definitely approximated by a poisson.
11. wow just looked at this thread... can't be bothered reading it. i did the exam before you all *imagine stick out tongue smiley*

thought it was ok considering i taught myself the course yesterday...

and i did poisson for that one btw

it's done. wooooooooooo

lou xxx
12. (Original post by Bhaal85)
Its getting repetitive, it's definitely approximated by a poisson.
lol yeah this is getting just a little annoying ; )
13. The paper could have been worse!

I used a 2-tail for the last question. I remember it asking for an effect in times without saying whether it was a good or bad one. I used poisson, with the value I calucluated from the question before which was actually 1.065 instead of using the value they gave you (1.05) probably a little silly of me! Apart from that can't think of any serious mishaps... hopefully claw back some of those marks I lost on M3...

Hardest question in my opinion was showing t4 + 60t3 + 1800t2 = 256350 (or whatever) - think I got it about 20 secs before exam finished (always relieveing)!
14. ok......
use of binomial, how many marks you wreckon

I bet at least one of the four for stating X~B(50,0.02)

1/4 marks... lol, gayed at the highest level
15. i reckon you'd get a couple of marks, one for stating the binomial and the other for doing a follow through calculation
16. Continuity correction.... was loving it...

Had a thing going with a friend, a cough per question to tell him if he had to do it, (he wasnt as happy with stats as i was)

Question 3.... 3 coughs..... he was loving it =D

sure its cheating though... lol
17. (Original post by tommyg)
ok......
use of binomial, how many marks you wreckon
if you think about it using the binomial makes more sense... it's exact for one. I think some of the marks were for showing you know how to approximate. In real life it wouldn't make sense!
18. Thanks sparrow184..... those ***** down at ocr... grr them
19. (Original post by sparrow184)
if you think about it using the binomial makes more sense... it's exact for one. I think some of the marks were for showing you know how to approximate. In real life it wouldn't make sense!
your're absolutly right....shame OCR didn't agree with you
20. beautiful paper. couldn't have complained. lost 2 marks with the 22/23 but it just didn't occur to me.COOOL

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