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I did awful on this, I did find the exam hard but didn't realise I was going to do so bad. Anyways, I'm resitting as it will bring my whole maths grade down and was just wondering if anyone could offer me any advice. Having done all the past papers for the Jan exam, I was doing well and felt prepared, but now I've lost all my motivation and find going through everything again is going to be tedious :/
Does anyone know how to work out these questions on normal approximation? I keep getting the wrong answer.
1. random variable X~Po(60) use a suitable approximation to estimate
a) P(X=63)
b) P(55 x<65)
Original post by oreoscookies
Does anyone know how to work out these questions on normal approximation? I keep getting the wrong answer.
1. random variable X~Po(60) use a suitable approximation to estimate
a) P(X=63)
b) P(55 x<65)


mean = 60 SD = square root of 60

1st one: 62.5 to 63.5

54.5 to 64.5 (you've got to include 55 but not 65)
I did use those values however, the answer in the book was different??
Reply 824
Does anyone know the grade boundaries for June 2012? Thanks :smile:
Reply 825
Out of curiosity, which chapter in S2 did people find the hardest? I'm just going through it now for the first time and not finding it too difficult.

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