(no subject)

[cheekbones3]

Being in a bad mood actually does make me want to post more! Anyone got any crap jobs they need doing? Collation of papers, file renaming that sort of thing. £5 an hour is my rate! In fact, I could do some tutoring actually. Maths, physics, or any science up to 16 year old level, plus geography and related I suppose. I really am that poor. Piss!

Comments

[toffeecat.livejournal.com]

One of the questions is

Suppose that x has a binomial distribution with n=200 and p=0.4

a) Show that the normal approximation to the binomial can appropriately to used to calculate probablities about x.

b)Make continuity corrections for each of the following, and then use the normal aprroximation to the binomial to find each probability
1) P(x=80)
2) P(x<65)
3) p(x>100)

[cheekbones3.livejournal.com]

Erm I never did this, but you can say for a) that the central limit theorem can be used to sum all the independent random variables that make up the binomial r.v., which means that the normal can be used when n is big enough, so mean =n.p and SD=sqroot(n.p.(1-p)).

b)1) Mean=80, SD=6.93, Z=see a table for the mid value of n=200 I think...
2) 0.0125
3) 0.002

I find that I'm actually bloody rusty, so this is helpful work for me as well - that's what I make those to be - could you tell me if I'm right? Lots of practise is the key...