Edexcel S2 - 27th June 2016 AM

Would I get any marks for this?! Question 5) Normal approx...X~B(n,0.2)E(X)=0.2nVar(X)=0.16ntherefore; X~N(0.2n,0.16n) P(X>55)=> CC P(X>=55.5)P(Z>(55.5-0.2n)/rt0.16n)=0.04011-P(Z<(55.5-0.2n)/rt0.16n)=0.0401P(Z<(55.5-0.2n)/rt0.16n)=0.9599Therefore;(55.5-0.2n)/rt0.16n = 1.7555-0.2n= 1.75(0.4)(n^1/2)55-0.2n=0.7n^1/2Then I squares out formed a quadratic and tried to rearrange but it didn't solve (yielded imaginary numbers) How many marks out of 8 would I get if any? Was I on the right lines or have I lost the plot.

Anyone with the model answers for the ial s2 paper

can't think of anything i got wrong (perhaps 6 part c i put 57 instead of 56) otherwise everything i put down was the same as people i have spoken to.

So i think minimum 72/75 (including random mistakes)

any ideas on grade boundaries?

The power was equal to 2(n) n was equal to 28 which multiplied by two was 56. Therefore the answer is 28.

Will I still get an A if I loose 10-12 marks max?

Anyone with the model answers for the ial s2 paper

I did!! wanna discuss the answers?

for this question I didn't end up with a quadratic... I had the mean = 0.02n and then variance i had it as 0.16n.. is this wrong ?

Bump someone answer please

you have to divide by sqrt(0.16n) when standardising

how many marks was the P(7<R<10) question

Where did I go wrong?

Q1-
1.41=1.4419 so mean=varaiance so use poisson
0.2510
0.7769
0.1378
0.1516

Q2-
n=60
0.0133
0.0159
not sure about this one someone please reply to this one: 23.69%>1% accept H0.

Q3-
1/2
151PI/3 REPLY TO THIS as well PLZ

Q4-
B=8
A=-12
K=1/9

Q5-
N=225

Q6-
57


Q7-
1.2
0.24
41.875 AND 40 REPLY TO THIS ONE IT IS ABOUT THE MONEY LAST ONE.

1 mark