Stats 2 (S2) OCR (not MEI) 22nd June 2012

how did u get the paper alreadyy ?!

thats not fairr. howd u find it

I was quite happy with it. There was nothing greatly taxing, but the only things I'm not 100% on are (2i) and (8iii).

For 2i) I calculated $\mathrm {Var}(\bar V)$, but I'm not sure whether or not I was supposed to reverse central limit theorem by multiplying my answer by 40. I did so and got an answer around 170-something.

As for 8iii), I think it should be $\mu \neq 30$, because $P(X \geq 4)$ was so low that it shouldn't have happened four times if $\mu = 30$.

and i got 173 for var (x)

i made x binominal with 20 and p 0.05
then found the p(x> and equal to 4)
then said i think mu is 30 because the probablity is small

I was quite happy with it. There was nothing greatly taxing, but the only things I'm not 100% on are (2i) and (8iii).

For 2i) I calculated $\mathrm {Var}(\bar V)$, but I'm not sure whether or not I was supposed to reverse central limit theorem by multiplying my answer by 40. I did so and got an answer around 170-something.

As for 8iii), I think it should be $\mu \neq 30$, because $P(X \geq 4)$ was so low that it shouldn't have happened four times if $\mu = 30$.

Yes you were supposed to multiply it by 40 as they asked for Var(V), i got 174 i think, something along those lines.

33.58


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Yes, good, I'm glad. I was just a touch unsure because the mean was far lower than the variance, which is unusual among OCR S2 questions. Thanks!

Np, i have to say this was a very nice paper. It's unfortunate for people who made silly mistakes (i'm so hoping i didn't, i rechecked like a mad man lol) as the grade boundaries are going to be very high. I'm guessing a 61/62 for an A but i'm no expert at this, it's just a guess.

As long as they aren't as high as the FP1 boundaries were in January. 67/72 for an A. That's over 90% for 80 UMS! I was very irritated to get a B in that module, probably due to stupid mistakes.

As long as they aren't as high as the FP1 boundaries were in January. 67/72 for an A. That's over 90% for 80 UMS! I was very irritated to get a B in that module, probably due to stupid mistakes.

67?! That's ridiculous, i can't believe that was even allowed. I'm glad i did mine last year.

your joking right :/ what the actual hell ?!

for the first 2 hypothesis tests, did everyone get 2 tailed?!

for the first 2 hypothesis tests, did everyone get 2 tailed?!

Yes . Btw how did you do 8iii)? I done 1-(p(x=0)+p(x=1)+p(x=2)) using s1 binominal rules. Not sure if i'm right though. I got a small value like 0.01 ish