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    well im delighted with how that went, thought that the paper wasnt particularly difficult and the error question (which i previously had trouble with) was about a discrete distribution , so i was pretty happy...
    over to you.,...
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    Think it went really well, have the paper here to scan and made a note of all my answers if somebody on here fancies a crack at the answers for us. Really good paper, considering the dreadful Mechanics 2 one last week.
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    (Original post by korobeiniki)
    Think it went really well, have the paper here to scan and made a note of all my answers if somebody on here fancies a crack at the answers for us. Really good paper, considering the dreadful Mechanics 2 one last week.
    May as well put it up anyway
    I agree with you two

    It was a great paper.
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    (Original post by Gallant92)
    May as well put it up anyway
    I agree with you two

    It was a great paper.
    Sure thing, scanning it now. What were your comments on the second claim for 5ii btw?
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    which question was that? :P
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    For the second claim I said there could have been other factors like affecting how many people went in the shop. I liked that paper, far nicer than all the past papers I've been doing
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    ahh that one, i put that it was impossible to say that the price cuts were the reason more people were in the shop
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    I thought it went well. It was quite different to all of the past papers which will mean that those who didnt really understand the methods and just rote learned certain question types will have done badly. For example the sign change rule and that question on "why are these probabilities not possible" will have thrown alot of people.

    Did anyone else waffle for about half a page to get 1 mark on one of the earlier questions?
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    not the best scans but all the info is there. Yeah I had a feeling afterwards they'd've wanted an answer like "impossible" I started rambling about how they should do further tests to confirm/ensure no errors before they made an unneccesary expense keeping the prices cut.
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    (Original post by korobeiniki)



    not the best scans but all the info is there. Yeah I had a feeling afterwards they'd've wanted an answer like "impossible" I started rambling about how they should do further tests to confirm/ensure no errors before they made an unneccesary expense keeping the prices cut.
    Thats a pretty good copy considering the time between now and the exam.

    Lets get some solutions up guys.
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    Ahh I think I got the first one wrong. I think the rest was kind of okay though I think.
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    Best way to do it, is probably people post up any queries and we discuss them
    unless we can convince Mr M or someone to put the answers up.
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    I wasn't meant to use central limits on q1 was I? Habit from the endless past papers when I did need to use it so I didn't think about it when answering this.
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    if you want ill post my answers? reckon i did quite well?
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    ooo that'd be good
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    q1: Mu = 15.16
    Var = 1.363
    2. about half a page of **** - if a student was in the first 200 - there would be more chance of him being picked (as say he was no. 150 - then the numbers 150, 550 or 950 would all choose him whilst a student between 200-399 would not have as much chance...
    improved - i put discarded all values above 399....
    3. normal - continuity correction making it 18.5 - got 0.251 as my final answer?
    4. Reject it - as i got 0.0247 - which is in the rejection region
    5. also reject it - i got the probability of 0.9907 - also in the rejection region
    6. i) probs dont add up to 1
    ii) >50 has to have a larger prob than > 70
    iii) says 50 is bigger than mu but 70 is less than mu...not possible
    Mu as 60 , S as 21.89 (although for some reason i think i wrote 218.9)
    7. drew a rectangle from 5-11 with height 1/6
    ii) e(x) = 8
    var = 67 - apparantly the varience is 67 - 64 = 3
    Thus next answer wrong...
    prob = 0.401 - and its apporx cause it can be distributed normally cause of central limit theorum?
    8.
    i)4.73%
    ii)0.3669
    iii)0.18345

    9. i) 0.0335 edit: i got this wrong apparently
    ii) 0.196
    iii) 0.8720
    iv) e^-3m + (e^-3m x 3m)
    just plugged both other values to show it lay in between..


    Just my answers - really doesnt mean they are right at all
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    I accepted H0 for 4 time wasn't underestimated

    I rejected H0 for 5, mean number of customers had increased.

    q 7 I put central limit theorem
    err can't remember all the figures but none that i'm sure are different except 5.

    7 ii var was 3 because you have to minus mean^2 (64)

    ?
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    (Original post by busbybabe)
    q1: Mu = 15.16
    7. drew a rectangle from 5-11 with height 1/6
    ii) e(x) = 8
    var = 67
    prob = 0.401 - and its apporx cause it can be distributed normally cause of central limit theorum?

    9. i) 0.0335
    ii) 0.196
    iii) 0.8720
    iv) e^-3m + (e^-3m x 3m)
    just plugged both other values to show it lay in between..


    Just my answers - really doesnt mean they are right at all
    9 part 1, you've calculated P(X>=7), when you needed P(X>7), the answer (from memory, so don't kill me plz) I think is 0.0119 or similar.

    The variance for 7 is 3, you show this by integration, but it's plainly obvious from looking at the graph. And as such your answer for the final probability is also wrong, due to error carried forward. I can't remember what I got for it though.

    I think I agree with the rest of it, in general, but as usual with stats remembering exact answers is always a bit hazy.
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    (Original post by busbybabe)
    7. drew a rectangle from 5-11 with height 1/6
    ii) e(x) = 8
    var = 67

    Just my answers - really doesnt mean they are right at all
    Var(X)= 67-8^2=3
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    mmm i thought the varience was weird - but so many people got that answer...
    its clear that f(x) was 1/6
    and integrate it between 11 and 5 for x2f(x) and you get 67??
    and 9 part 1....im retarded
 
 
 
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