Edexcel S2 - 27th June 2016 AM

can someone check june 2006 question 7a and tell me why it is a binomial and not a poisson?>

If anyone feels **** about tomorrow, just remember I started revision an hour ago

I think that would be some consolation if you weren't the Student403

Part (c): can anyone explain why {[P(X] intersection P(X = 4)} becomes P(X = 1) × P(X = 3) here?

that doesn't quite make sense as far as I can see.

Something like $P(X_1 = 1 , X_2 = 3 | X_1 + X_2 = 4) = P(X_1 = 1 \cap X_2 = 3 \cap X_1 + X_2 = 4) =P(X_1 = 1) \times P(X_2 = 3)$ where the X1 + X2 disappears because it is implied/true by the other statement.

by independence would make more sense.

Tomorrow will probably be the hardest S2 with lots of conditional probabilities and in-context uniform distribution.

@SeanFM


For the last part of this question I integrated from 1.5 to 2.5. However in the mark scheme they did 1 - integral 1.5 to 2.5. Do you know why?

@SeanFM


For the last part of this question I integrated from 1.5 to 2.5. However in the mark scheme they did 1 - integral 1.5 to 2.5. Do you know why?

What do you mean by in-context uniform distribution?

For continuous uniform distribution e(x) is the same as the median and the mean?

@SeanFM

https://ef8b5216a7366459ac0f2ce0ac13ad2bbcf4d40a.googledrive.com/host/0B1ZiqBksUHNYQVk0YTh4MUlET0E/for-Edexcel/Solomon%20B%20QP%20-%20S2%20Edexcel.pdf

Like question 3

Because the integral finds probability of being between those two numbers, when you want it to be on either side of those numbers, if that makes sense.

You are looking for the probability of waiting either less then 1.5 or more than 2.5