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# S2 watch

1. So I've worked through a paper have a few things I couldn't do.

The last bit of question 9. So I have found the values needed and it comes out as needing to find the Phi of (3.494)- Phi of (-1.655).
The problem is in the normal tables it doesn't go up to the phi of 3.494...

http://www.ocr.org.uk/Images/78550-q...atistics-2.pdf

Thanks.
2. (Original post by Music99)
So I've worked through a paper have a few things I couldn't do.

Question 5, I think it's Binomial distributed, but I got the wrong answer.

And the last bit of question 9. So I have found the values needed and it comes out as needing to find the Phi of (3.494)- Phi of (-1.655).
The problem is in the normal tables it doesn't go up to the phi of 3.494...

http://www.ocr.org.uk/Images/78550-q...atistics-2.pdf

Thanks.
Use your answers to the first part of the question and use Poisson to estimate Binomial.
3. (Original post by Lunch_Box)
Use your answers to the first part of the question and use Poisson to estimate Binomial.
I meant the very first part of question 5 sorry. I had another look but I'm slightly confused I know it's Binomial so I can use the formula for calculating exactly equal to four, but I'ma bit unsure on which parameter to take for n and p in this case.
4. (Original post by Music99)
I meant the very first part of question 5 sorry. I had another look but I'm slightly confused I know it's Binomial so I can use the formula for calculating exactly equal to four, but I'ma bit unsure on which parameter to take for n and p in this case.
You can use the binomial formula then I'm guessing.

P(girl) = 12/20
P(boy) = 8/20
n = 6
5. (Original post by Lunch_Box)
You can use the binomial formula then I'm guessing.

P(girl) = 12/20
P(boy) = 8/20
n = 6
Ahh right makes sense. But then i'm a bit unsure on the bit with it saying more then one person can win a prize, doesn't that affect the calculation?
6. Bump.
7. Bump.
8. Bump!

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