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Edexcel S2 - 27th June 2016 AM

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Original post by M3WIZARD
Question 1a) U = 1.44 Var(x) = 1.44 (3 Marks)b) U was approximately Variance (1 Mark)c) I 0.251 II 0.777 (4 Marks)d) 0.1378 (3 Marks)e) 0.152 (3 Marks) (Might be 0.132 Rushed this onmy copy of answers) Question 2a) N=60 (2 Marks)b) I 0.0133 II -0.0159 (5 Marks)c) 0.2396>0.01 Keep H0 (5 Marks)Question 3a) f(x) = ¼ 5=<R=<9 , 0 otherwise (1 Marks)b) 0.5 (1 Marks)c) 158.13 (4 Marks)Question 4a) Show that (6 Marks)b) K = 1/9 (4 Marks)Question 5 N = 225(I applied continuity correction I honestly didn’t know if I should) (8Marks)Question 6a) 9 samples (2 Marks)b) 4 = ¼ , 5 = 3/10 , 6= 29/100 , 7 = 3/25, 8 =1/25 (5 Marks)c) N=57 (3 Marks)Question 7a) 1.2 (4 Marks)b) 0.24 (4 Marks)c) 0.325 (3 Marks)d) £41.88 (2 Marks)e) Shouldn’t remove staples (2 Marks) I’m not claiming these are all right let me know J These are what I wrote


Most of them is correct. Well done
Original post by TheSammy2010
My answers, idk if they are right

Q1,
Mean= 1.41
Variance= 1.4419
Probabilities; 0.7769, 0.1378, 0.1516

Q2,
N=60
0.0133
0.0159
Do not reject Ho (using binomial tables)

Q3,
0.75
151π/3

Q4,
K=1/9

Q5,
N=225

Q6,
P(M=5)= 0.3
P(M=6)= 0.29
P(M=7)= 0.12

N=11

Q7,

Mean= 1.2
Var= 1.92
P(X>3)= 0.3250
£41.88 per bin

He shouldn't as the mean profit of bins would be £40

Q6 I got N=57


Original post by Student1408
i got 225!!!

FLIP yeah!!! last exam forever!!!!!

FREEEEEEDOMMMM!:p:)


Original post by connorbarr
225 as well


Original post by LLk1
Did you have to do continuity correction for the normal distribution question? I put in 55.5 and got a nice answer of 225, I then tried with just 55 and got not such a nice answer....


Ok, seems like I made a mistake in this big 8 marker...
Did you do normal approximation from binomial to normal?
With the normal approximations having n in it?
I got a quadratic involving n in the end...! Slip or big error?
What was the method for question 1a !! I got the answer as -19560 which is obviously wrong - someone please explain lol
Original post by M3WIZARD
Question 1a) U = 1.44 Var(x) = 1.44 (3 Marks)b) U was approximately Variance (1 Mark)c) I 0.251 II 0.777 (4 Marks)d) 0.1378 (3 Marks)e) 0.152 (3 Marks) (Might be 0.132 Rushed this onmy copy of answers) Question 2a) N=60 (2 Marks)b) I 0.0133 II -0.0159 (5 Marks)c) 0.2396>0.01 Keep H0 (5 Marks)Question 3a) f(x) = ¼ 5=<R=<9 , 0 otherwise (1 Marks)b) 0.5 (1 Marks)c) 158.13 (4 Marks)Question 4a) Show that (6 Marks)b) K = 1/9 (4 Marks)Question 5 N = 225(I applied continuity correction I honestly didn’t know if I should) (8Marks)Question 6a) 9 samples (2 Marks)b) 4 = ¼ , 5 = 3/10 , 6= 29/100 , 7 = 3/25, 8 =1/25 (5 Marks)c) N=57 (3 Marks)Question 7a) 1.2 (4 Marks)b) 0.24 (4 Marks)c) 0.325 (3 Marks)d) £41.88 (2 Marks)e) Shouldn’t remove staples (2 Marks) I’m not claiming these are all right let me know J These are what I wrote

Yeah same for all except don't remember 3(c)
What was the question for 3 (c)?


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looking at these answers, feel like i made a lot of mistakes but oh well, just one left now
Reply 686
Original post by qqa85781521
Q6 I got N=57


I got n= 177 :'( (or something like that)
Original post by Gilo98
Should be around 72/75 for me. Make a stupid mistake on a and k question. Found the first simultaneous equation so I imagine there's a mark in that. IIRC correctly it was 4 marks so the other 3 will be dropped. Paper was quite a fair bit easier that I thought it would be. I predict high grade boundaries


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yeah, it was easier because most past papers i did had a least more than one hypothesis testing and they had definitions but todays didn't. I hope GB arent too high!
Original post by M3WIZARD
Question 1a) U = 1.44 Var(x) = 1.44 (3 Marks)b) U was approximately Variance (1 Mark)c) I 0.251 II 0.777 (4 Marks)d) 0.1378 (3 Marks)e) 0.152 (3 Marks) (Might be 0.132 Rushed this onmy copy of answers) Question 2a) N=60 (2 Marks)b) I 0.0133 II -0.0159 (5 Marks)c) 0.2396>0.01 Keep H0 (5 Marks)Question 3a) f(x) = ¼ 5=<R=<9 , 0 otherwise (1 Marks)b) 0.5 (1 Marks)c) 158.13 (4 Marks)Question 4a) Show that (6 Marks)b) K = 1/9 (4 Marks)Question 5 N = 225(I applied continuity correction I honestly didn’t know if I should) (8Marks)Question 6a) 9 samples (2 Marks)b) 4 = ¼ , 5 = 3/10 , 6= 29/100 , 7 = 3/25, 8 =1/25 (5 Marks)c) N=57 (3 Marks)Question 7a) 1.2 (4 Marks)b) 0.24 (4 Marks)c) 0.325 (3 Marks)d) £41.88 (2 Marks)e) Shouldn’t remove staples (2 Marks) I’m not claiming these are all right let me know J These are what I wrote


for the very last question, did you find that the E(X) was £40 and then said that this was less than the value found in part E?
Reply 689
Original post by Student1408
i got 225!!!

FLIP yeah!!! last exam forever!!!!!

FREEEEEEDOMMMM!:p:)


Last exam FOREVER?!
Are you not going to University then?
Think I got like 60 so shouting myself as I don't know whether I've gotten an a or b overall in maths


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Original post by qqa85781521
Q6 I got N=57


That's probably right, I didn't really understand the question
Original post by TheSammy2010
My answers, idk if they are right

Q1,
Mean= 1.41
Variance= 1.4419
Probabilities; 0.7769, 0.1378, 0.1516

Q2,
N=60
0.0133
0.0159
Do not reject Ho (using binomial tables)

Q3,
0.75
151π/3

Q4,
K=1/9

Q5,
N=225

Q6,
P(M=5)= 0.3
P(M=6)= 0.29
P(M=7)= 0.12

N=11

Q7,

Mean= 1.2
Var= 1.92
P(X>3)= 0.3250
£41.88 per bin

He shouldn't as the mean profit of bins would be £40


Qu 2d, because n isn't greater than 50 u don't approximate it and so i got 0.2252 (don't remember exactly) is greater than 0.5 and so accept H0 supports statement
Original post by TheSammy2010
My answers, idk if they are right

Q1,
Mean= 1.41
Variance= 1.4419
Probabilities; 0.7769, 0.1378, 0.1516

Q2,
N=60
0.0133
0.0159
Do not reject Ho (using binomial tables)

Q3,
0.75
151π/3

Q4,
K=1/9

Q5,
N=225

Q6,
P(M=5)= 0.3
P(M=6)= 0.29
P(M=7)= 0.12

N=11

Q7,

Mean= 1.2
Var= 1.92
P(X>3)= 0.3250
£41.88 per bin

He shouldn't as the mean profit of bins would be £40


I agree with all of these, except n=57 on question 6
Original post by fefssdf
What was the method for question 1a !! I got the answer as -19560 which is obviously wrong - someone please explain lol


Its basically sum of fx /divided my the sum of f

and for variance its E(X^2)- (E(X))2. meaniing the sum of fx^2 insead.

That sounds confusing lol but its usually in s1 but they put it on s2.

Hope that helps!! :smile:
Reply 695
What were the values of a, b and k in that question?
Original post by PatBunker
I agree with all of these, except n=57 on question 6


yeah, it's probably wrong :colonhash:
Please vote in the poll http://www.thestudentroom.co.uk/showthread.php?t=4188821
(Expect high grade boundaries)
Original post by M14B
Last exam FOREVER?!
Are you not going to University then?


Oh yeah lol sorry. :colondollar:LAST EXAM ( for P(X-less than 365 days) lol :biggrin::smile:
Original post by TheSammy2010
My answers, idk if they are right

Q1,
Mean= 1.41
Variance= 1.4419
Probabilities; 0.7769, 0.1378, 0.1516

Q2,
N=60
0.0133
0.0159
Do not reject Ho (using binomial tables)

Q3,
0.75
151π/3

Q4,
K=1/9

Q5,
N=225

Q6,
P(M=5)= 0.3
P(M=6)= 0.29
P(M=7)= 0.12

N=11

Q7,

Mean= 1.2
Var= 1.92
P(X>3)= 0.3250
£41.88 per bin

He shouldn't as the mean profit of bins would be £40

What was Q3 about?

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