Edexcel S2 - June 22nd, 2015 [Exam discusison thread]

Isn't that just covered in S1?

in past papers they sometimes set like 8 marks of the paper down to asking you to define words such as census etc. I have looked through the s2 specification on the edexcel website but cant actually find anything which says what definitions we need to know, i dont suppose someone happens to have a list of potential words and definitions?

Its in S1. Think of it as any mean from a table. "Sum of fx over the sum of f" where f is the probabilities P(X=x). The sum of probabilities is 1 hence why we ignore the "over f" bit.

Sum of f x means sum of x times the P(X=x).

Then I could not possible explain it to you, but make a note of this for when you do M3, so long again you do things from first principles (no stupid formulas)

the continuous version of the E(X) is the x coordinate of the centre of mass of a lamina of unit mass, which has the shape of you PDF, i.e the balancing point of the lamina in the x direction.

the discrete version of the E(X) is the x coordinate of the centre of mass of n particles whose total mass is 1, the P(x) represents their relative mass.
i.e the "balancing point" again in the x direction.

in past papers they sometimes set like 8 marks of the paper down to asking you to define words such as census etc. I have looked through the s2 specification on the edexcel website but cant actually find anything which says what definitions we need to know, i dont suppose someone happens to have a list of potential words and definitions?

https://57a324a1a586c5508d2813730734691051ac35fd.googledrive.com/host/0B1ZiqBksUHNYZ3M4QzJ0N19IeHc/January%202012%20QP%20-%20S2%20Edexcel.pdf

i dont understand question 2. Its a two tail test but only testing one tail ( i know its one sided results) but your changing the sig. level, instead of 2.5% each tail. thanks for any help

look at post 187

thank you so much!

Question:
When doing a two-tailed hypothesis test, how do you know which tail to select?
P(X>x) or P(X<x)?

Question:
When doing a two-tailed hypothesis test, how do you know which tail to select?
P(X>x) or P(X<x)?

Just did the May 2011 paper, well ****.