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    The very last question on the June 2001 paper has a B(75, 0.08). As n is large and p is small, you could use the poisson distribution as an approximation, but as np >5 and np(1-p) > 5 you could use the normal distribution as an approximation.

    Which one should I use? Why?

    Many thanks.
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    (Original post by seankhn)
    The very last question on the June 2001 paper has a B(75, 0.08). As n is large and p is small, you could use the poisson distribution as an approximation, but as np >5 and np(1-p) > 5 you could use the normal distribution as an approximation.

    Which one should I use? Why?

    Many thanks.
    You would use the poisson, because n is large and p is small, normal would be used when the distribution is fairly symmetrical and p is large
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    Only use the normal when p is large?

    What if it were B(750, 0.08)?

    Surely a normal approximation would be a better idea than Po(60)?
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    (Original post by seankhn)
    Only use the normal when p is large?

    What if it were B(750, 0.08)?

    Surely a normal approximation would be a better idea than Po(60)?
    yeh, use normal, cos poisson tables dont go that high - i just multiply stuff and if can't use one thing, use the other - process of elimination

    pk
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    You always try to use the Poisson for the Binomial approximation because both are discrete and so its more accurate. Only use the normal when the poisson can't be used (i.e when np > 10)
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    Thanks folks.
 
 
 
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