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OCR MEI - Statistics 1 - Monday 19th Jan 09

Just wondering how people found this? there were couple of probabilities in section were bit iffy, but i found section B alright. The cumulative freq. graph was a godsend and the hypothesis bit wasn't too bad either.

What did you guys think, those that took it? :smile:

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Reply 1

plopSDCSDC

Am i the only one that took the paper? lol

Reply 2

dramaminedreams

Yes I agree with that. Loved the cumulative frequency stuff. I've got all my answers written down on the paper so I'll post what I think it is later.

Reply 3

Chriz M

I thought the paper was good, except the first question where you had to assume that there had been no lottery tickets sold. Otherwise a straight forward paper.

Reply 4

dramaminedreams

1i) Mean = 0.75, Standard Deviation = 50.14
ii) 0.000029

2i) 1/720
ii) 1/20

3i) p=0.55
ii) E(X) = 1.35, VAR(X) = 2.9275
iii) 0.1225

4i) 0.3372
ii) 0.4447
iii) 160 batches?

5i) Dependent
ii)-
iii) 5/9 but I drew the Venn diagram wrong, so this will also be wrong

6i) Median = 4.05
IQR = 0.5
ii) Just LQ-1.5IQR and UQ+1.5IQR
iii) No
iv) 25,125,243,157,50
v) Mean = 4.055
vi) Mean (F) = 39.299, SD (F) = 0.6822

7i) 0.30199, 0.6788
ii) Accept H0
iii) Critical region is X <(eq) 10 and X>(eq)17. Therfore accept H0. Statistician is wrong wrong wrong wrong wrong and gay ( I actually put that in my exam, so I hope I am right about the actual answer otherwise epic fail!)

Reply 5

vivalavida22

Can anyone remember the Standard deviation value for question 1 about the scratchcards?

Reply 6

MetalHed

i think it went ok but are we allowed to talk about it yet? i thought there was a rule about ocr exams and we had to wait 24 hours or something.. :confused:

not sure, i might be wrong!

Reply 7

plopSDCSDC

what? i put that the critical region for Q7 part ii as emtpy for the lower tail?

Reply 8

julija

dramaminedreams

1i) Mean = 2.55, Standard Deviation = 50.14
ii) 0.000029

2i) 1/720
ii) 1/20

3i) p=0.55
ii) E(X) = 1.35, VAR(X) = 2.9275
iii) 0.1225

4i) 0.3372
ii) 0.4447
iii) 160 batches?

5i) Dependent
ii)-
iii) 5/9 but I drew the Venn diagram wrong, so this will also be wrong

6i) Median = 4.05
IQR = 0.5
ii) Just LQ-1.5IQR and UQ+1.5IQR
iii) No
iv) 25,125,243,157,50
v) Mean = 4.055
vi) Mean (F) = 39.299, SD (F) = 0.6822

7i) 0.30199, 0.6788
ii) Accept H0
iii) Critical region is X <(eq) 10 and X>(eq)17. Therfore accept H0. Statistician is wrong wrong wrong wrong wrong and gay ( I actually put that in my exam, so I hope I am right about the actual answer otherwise epic fail!)

damn, for 7 iii) i've put X>(eq)18 :o:

Reply 9

JjrShah

MetalHed

i think it went ok but are we allowed to talk about it yet? i thought there was a rule about ocr exams and we had to wait 24 hours or something.. :confused:

not sure, i might be wrong!

Think that's just Edexcel

Reply 10

fletn22

julija

damn, for 7 iii) i've put X>(eq)18 :o:

me too

i hope that's right, i got very confused with all the signs haha!

also put £0.75 for 1(i) but i think that could be wrong

Reply 11

dramaminedreams

This is what I did for the last question
P(X>a)<0.025
1-P(X<a)<0.025
1-P(X<17)=1-0.9820=0.018 which is less than 0.025

Crap, do you have to add one at the end? I didn't think you did, but I may be wrong.

Reply 12

MetalHed

JjrShah

Think that's just Edexcel

ahh ok thanks.

Reply 13

MetalHed

fletn22

me too

i hope that's right, i got very confused with all the signs haha!

also put £0.75 for 1(i) but i think that could be wrong

me too, i'm pretty sure it was right.

Reply 14

dramaminedreams

fletn22

me too

i hope that's right, i got very confused with all the signs haha!

also put £0.75 for 1(i) but i think that could be wrong

That's right sorry, I put 2.55 first then realised I had done it wrong.

Reply 15

plopSDCSDC

yeah i put £0.75 for 1) i) too, but i could be wrong.

Did anyone remember what they put for question 2 or 3 i think in Section A. about picking the name Thomas or soemthing, using nCr and nPr?

Reply 16

alixxxxxx1

plopSDCSDC

yeah i put £0.75 for 1) i) too, but i could be wrong.

Did anyone remember what they put for question 2 or 3 i think in Section A. about picking the name Thomas or soemthing, using nCr and nPr?

1. 1/6! so 1/720
2. 1/6x3 so 1/20

Reply 17

alixxxxxx1

dramaminedreams

1i) Mean = 0.75, Standard Deviation = 50.14
ii) 0.000029

2i) 1/720
ii) 1/20

3i) p=0.55
ii) E(X) = 1.35, VAR(X) = 2.9275
iii) 0.1225

4i) 0.3372
ii) 0.4447
iii) 160 batches?

im sure this was 240 x 0.3372 so was 80 something :s-smilie:

Reply 18

JBKProductions

plopSDCSDC

yeah i put £0.75 for 1) i) too, but i could be wrong.

Did anyone remember what they put for question 2 or 3 i think in Section A. about picking the name Thomas or soemthing, using nCr and nPr?