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OCR MEI Statistics (S1) - 25th January 2013

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Reply 160
Original post by Rapidzx
So now that the unofficial mark scheme is up what do people think they got? :smile:


We've got the answers, but we dont know the marks for the individual questions, does anyone how much each Q is worth too?
Original post by Attz_09
i got 2/33
by i think it was 11 dogs choose 3
5 terriers out of the 11 dogs
what is the probability that 2 terriers are in the 3 dogs that were chosen(5 marks)
all i did was
5C2/11C3

any correction please reply include what i needed to improve also i might of forgotten part of the question so feel free to add any extra bits to corrections lol



Didn't the Q actually say 'at least 2 terriers?, I doubt that 5C2/11C3 would get full marks. I think that it was a binomial question, since it said 5 out of 11 dogs were terriers, therefore, the rest were not.
Original post by Rapidzx
There was.
The only outlier was 8.1 I believe.


Blast!

Thanks to my dodge eyes, I never saw that there was a decimal point, and had all my numbers 10 times too big.

How many marks lost for the stupid error of misreading the question?
Reply 163
Thats the wrong order

1. question about standard deviation/mean/skewness
2.E(x) and var(x)
3. venn diagram
4. dogs question
5. malik's dice question
6. histogram question
7.hypotheses question

Also anyone get 5/6 times 5/6 times 1/6 for 5 part 1
and i also got that for 7 part 1 10 was not in the critical region so accept h0
then for the second part reject h0
I screwed up the venn diagram, but nailed the malik dice game and the dogs question,
for the question about finding the median height of the boys, i took the 50th value, which was the 4th value in the group 145-150 ( because the first group had 25, second had 29, so it is the fourth)
Then, i did 150-145 = 5, divided by the 29 in the group = 5/29, then i multiplied this by 4 which gave me 0.69, i then added this onto the starting value for the group, so i got around 145.69, how ever i cant remember the class, it might have been 140-145, or 145-150, either way is that the right method? Or did i screw it up? XD
I screwed up the venn diagram, but nailed the malik dice game and the dogs question,
for the question about finding the median height of the boys, i took the 50th value, which was the 4th value in the group 145-150 ( because the first group had 25, second had 29, so it is the fourth)
Then, i did 150-145 = 5, divided by the 29 in the group = 5/29, then i multiplied this by 4 which gave me 0.69, i then added this onto the starting value for the group, so i got around 145.69, how ever i cant remember the class, it might have been 140-145, or 145-150, either way is that the right method? Or did i screw it up? XD Hopefully the grade for an A will be around 54, and i'll get maybe 58ish since i mucked up the venn diagram
Reply 166
Original post by lmaoyoudied
I screwed up the venn diagram, but nailed the malik dice game and the dogs question,
for the question about finding the median height of the boys, i took the 50th value, which was the 4th value in the group 145-150 ( because the first group had 25, second had 29, so it is the fourth)
Then, i did 150-145 = 5, divided by the 29 in the group = 5/29, then i multiplied this by 4 which gave me 0.69, i then added this onto the starting value for the group, so i got around 145.69, how ever i cant remember the class, it might have been 140-145, or 145-150, either way is that the right method? Or did i screw it up? XD Hopefully the grade for an A will be around 54, and i'll get maybe 58ish since i mucked up the venn diagram


I did what you did for the median but used 50.5 as I thought you have to find the median position as 100+1 / 2!
Reply 167
for the median question for secion b if I said that the median was the class of 140<x<145 as I thought i had to find the median position by doing 100+1 / 2 and that gave me a value of 50.5 and use cumulative frequency to show that it was in the region of 140<x<145 how many marks would that give me?
does anyone remember what value they got for the mean for girls? i got 146.875?

Posted from TSR Mobile
Reply 169
Original post by Rubyturner94
does anyone remember what value they got for the mean for girls? i got 146.875?

Posted from TSR Mobile


I'm pretty sure I got that.
I left my answer for 4 significant figures
Original post by Rapidzx
I'm pretty sure I got that.
I left my answer for 4 significant figures


me too :biggrin:

Posted from TSR Mobile
Slightly fustrated, for some reason I decided to change my hypothesis test to a 1 tail test after doing it correct. Pretty sure I did the one tail test and then applied the hypothesis and significance levels to the final part of the question also. How many marks do you think I'll lose (9 Mark hypothesis test and then 2 marks for the context)?

Thought this exam was pretty nice if I'm honest. I think the boundaries will be 57 or so for an A. Hopefully not though, it was pretty easy to drop silly marks I thought.
Reply 172
Urgh! Forgot to half the critical region for the last two questions :frown:
How many marks do you guys think I'll lose overall for this error? :smile:
Original post by Rapidzx
Urgh! Forgot to half the critical region for the last two questions :frown:
How many marks do you guys think I'll lose overall for this error? :smile:


I think 2, 1 mk for not halving and the 2nd for accuracy on the critical region.
It seems the mark for an A was 49.

I got 90 UMS although I thought I had pretty much aced the exam. By contrast, I got 100 for FP1 and FP2 despite messing up FP1 to the extent that I was planning to resit.

This marking scheme is just weird.
Reply 175
Original post by stevencarrwork
It seems the mark for an A was 49.

I got 90 UMS although I thought I had pretty much aced the exam. By contrast, I got 100 for FP1 and FP2 despite messing up FP1 to the extent that I was planning to resit.

This marking scheme is just weird.

I think it was 57 for 80 ums(grade A) so if you got 90 ums you must have pretty much aced it
I got my results back on 7th March for Statistics1: GRADE A :biggrin:

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