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    can someone show how you do question 5i
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    (Original post by arronpile)
    I got up to O~=0.03/1.645 how many marks out of 6 do you think I got
    About 3, you did half of the question right so half marks dropped I'd say.
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    (Original post by arronpile)
    can someone show how you do question 5i
    H0: p = 0.55
    H1: p > 0.55

    G~B(8,0.55)
    P(G>=6) = 1 - P(G<=5) = 1-0.7799 = 0.2201

    As 22.01% > 10%, accept H0.
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    (Original post by tinkerbella~)
    H0: p = 0.55
    H1: p > 0.55

    G~B(8,0.55)
    P(G>=6) = 1 - P(G<=5) = 1-0.7799 = 0.2201

    As 22.01% > 10%, accept H0.
    p(G>6)=1-P(G<or equal to 6) isn't that right??
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    (Original post by arronpile)
    p(G>6)=1-P(G<or equal to 6) isn't that right??
    But you want P(G>=6), you test for the probability of getting the test statistic or a more extreme value.
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    (Original post by tinkerbella~)
    But you want P(G>=6), you test for the probability of getting the test statistic or a more extreme value.
    I did it for P(G>6) so how many marks you think I dropped
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    (Original post by arronpile)
    I did it for P(G>6) so how many marks you think I dropped
    Honestly I have no idea sorry! Somebody else on here might have a clue though
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    (Original post by arronpile)
    I did it for P(G>6) so how many marks you think I dropped
    Somewhere between 2-4 marks, probably 2 or 3 because it still gives you the same conclusion.
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    Did you have to multiply the sample variance by n/n-1 in 8ii?
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    (Original post by madberry1)
    Did you have to multiply the sample variance by n/n-1 in 8ii?
    Yes
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    Any idea what the mark distribution is for 8ii)? I forgot to work out the actual population variance but worked out that it if it was greater than 12.45 it would result in Ho being accepted... I'm worried that I'll lose all/most the marks though
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    (Original post by rtycoss)
    Any idea what the mark distribution is for 8ii)? I forgot to work out the actual population variance but worked out that it if it was greater than 12.45 it would result in Ho being accepted... I'm worried that I'll lose all/most the marks though
    5 marks.
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    so for Q8 I did part i in part ii and in part i I just did it without dividing by 50. Got the last part right, got the ho/1, any chance I'll get the marks for doing part i in ii? How many marks should I get over the Q??
    Any help is appreciated
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    (Original post by TheNicholas)
    so for Q8 I did part i in part ii and in part i I just did it without dividing by 50. Got the last part right, got the ho/1, any chance I'll get the marks for doing part i in ii? How many marks should I get over the Q??
    Any help is appreciated
    For using the wrong variance on part i) You will probably lose 2 accuracy marks and the conclusion because the conclusion is usually dependent on the correct value.
    For ii) I have no idea.
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    (Original post by WorkHardGoToUni)
    For using the wrong variance on part i) You will probably lose 2 accuracy marks and the conclusion because the conclusion is usually dependent on the correct value.
    For ii) I have no idea.
    Thank you for your reply
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    (Original post by xsanda)
    Xsanda's solutions

    1) Unbiased mean and variance of summarised data
    E(V) = 268
    Var(V) = 1912/13 = 147 [4]

    2) Normal distribution, given P(M<1.00) = 5%
    P(M>1.05) = 13.6% [6]

    3) Approximated binomial
    n large, np = 26 > 5, nq = 14 > 5
    use normal distribution
    P(X<=30) = 0.932 [7]

    4) Poisson, P(X=4) = P(X=5)
    λ = 5, P(X=5) = 0.175 [5]

    5) School with 55% girls
    i) P(G≥6) = 22% (above significance level), do not reject H₀ [7]
    ii) Fixed prob of girl chosen, independent of previous Head Students [1]

    6) Cars along a narrow road
    i) Constant probability of cars throughout the minute, cars independent [2]
    ii) λ = 6.5, P(4≤X<7) = 0.561[3]
    iiia) N(30,30)
    P(X>35) = 0.158 [6]
    b) Not independent (narrow, slow road, so affected by car in front) [1]

    7) Probability density function
    i) x is a single sample value of X [1]
    ii) a=1, b=1.5 [7]
    iii) E(X) = 7/4 = 1.75 [3]

    8) Animals dying at zoo
    i) P(L<12.48) = 4.88% < 5%
    reject H₀, substantial evidence zoos limit life expectancy [7]
    ii) s² = 12.5
    5.05% > 5%, do not reject H₀, insufficient evidence zoos limit life expectancy [5]
    iii) yes, as the distribution of the original data is not given [1]

    9) Poisson test, λ=11
    i) reject if P(R≥20)
    92% chance of Type II error [6]
    I did 8i and ii completely correctly but just the wrong way around. I used 12.5 for i and 12.25 for ii... How many marks u reckon worst case I could have lost out of 12??? .. part i being worth 7 and part ii being worth 5. Thanks
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    (Original post by TheNicholas)
    Thank you for your reply

    i did the same how many marks do you think we'll lose?
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    (Original post by Yazmin123)
    i did the same how many marks do you think we'll lose?
    Considering we got iii right, I'd say anywhere from 6-11
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    can someone please explain the steps to get the answer to q8ii
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    (Original post by nao9)
    can someone please explain the steps to get the answer to q8ii
    Use the n/(n-1) formula to calculate an unbiased estimate of the population variance from the sample variance. Then carry out the hypothesis test just like in part (i).
 
 
 
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