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[Official Thread] OCR MEI AS Mathematics 2016 (C1, C2 & S1)

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Reply 520

sqr00t

Original post by Crozzer24

The final bracket should be multiplied by 3! as there is different combinations within those 3.

aye ****mylife. there goes two marks

Reply 521

erinls2

Original post by jn998

The Women's percentage was definitely lower than the mens, 15.7<20.2

For this one I made a stupid mistake - I wrote down exactly the right working but accidentally wrote down 2.02 rather than 20.2 even though my working gave the correct answer. How much would I lose for this? I said you couldn't be certain because of the grouped data though- do you think I'd only lose one mark for this?

Reply 522

sqr00t

Original post by kennyboy69.5

same most people did but i think the answer is 4 because you had to find the mid of 27.7 and 27.9 instead of just 27.7 for the LQ. and for UQ mid of 31.6 and 32 instead of just 31.6

think in terms of a cumulative frequency graph. Q3 is 31.6, Q2 is 27.7. IQR=3.9. we could to the 15th value for Q3 from the first value. (left to right, top to bottom).

Reply 523

sqr00t

Original post by jn998

The Women's percentage was definitely lower than the mens, 15.7<20.2

My percentages was exclusive to each data set, so I worked out a percentage for women's and a percentage for men's. Worked out women's was higher than mens

Reply 524

phoebeisgreat

How did you calculate the percentage of the women's shoe question?

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Reply 525

ppe/gov&econ

Original post by sqr00t

think in terms of a cumulative frequency graph. Q3 is 31.6, Q2 is 27.7. IQR=3.9. we could to the 15th value for Q3 from the first value. (left to right, top to bottom).

No you would only do this for grouped data where there is a degree of error anyway. Because the data was discrete, q1 was 5.5th term and q3 was 15.5th term giving iqr=4

(edited 7 years ago)

Reply 526

WuMyster

Original post by sqr00t

You're supposed to use P(X=2).

No I assure you, you don't.

Reply 527

erinls2

Original post by phoebeisgreat

How did you calculate the percentage of the women's shoe question? [\QUOTE]

For me - I thought well the gap between 80 and 200 is 120, and 100 is 1/6 of the way into that. So 5/6 of the shoes, assuming even distribution, are £100 or more. So I did the frequency multiplied by 5/6 and then divided that by 930 and multiplied by 100 to get the percentage :smile:

Reply 528

♥Samantha♥

Original post by 5431

why have you deleted it you won't actually be disqualified??

I got really paranoid but someone else posted it now

Reply 529

♥Samantha♥

Original post by sqr00t

think in terms of a cumulative frequency graph. Q3 is 31.6, Q2 is 27.7. IQR=3.9. we could to the 15th value for Q3 from the first value. (left to right, top to bottom).

Cumulative frequency is only for continuous/grouped

(edited 7 years ago)

Reply 530

Delma

Argh for the IQR part of Q1 I used the 5.25th value for the LQ and the 15.25th value for the UQ so my IQR was 3.95. I don't know if that's right or wrong but it's close to 4 so I still got the outliers bit. I hope I don't lose too many marks for it though... can't believe the first question was the one I left until the end looool

Reply 531

♥Samantha♥

The MS usually accepts lots of different answers bc no one knows the 'correct' method. Like some are told to take the midpoint of the two numbers for the quartiles while some are taught to interpolate using (n+1)/4 and 3(n+1)/4

Reply 532

♥Samantha♥

Original post by Crozzer24

The final bracket should be multiplied by 3! as there is different combinations within those 3.

Oh crap I forgot about that :/ how many marks would I lose?

(edited 7 years ago)

Reply 533

jaseho98

Didn't you guys found the phrasing of Q2 part 3 really weird about the "exactly 2 occurs wins draws loses". I was so stuck and I've definitely lost all my marks there lolol

Reply 534

jn998

Original post by ppe/gov&econ

No you would only do this for grouped data where there is a degree of error anyway. Because the data was discrete, q1 was 5.5th term and q3 was 15.5th term giving iqr=4

Going to have to disagree with this. I got LQ 27.75, UQ 31.9 IQR 4.15

The median is the 10.5th value for 20n and the median is equal to double the LQ, hence the LQ is the 5.25th value, making the UQ the 15.75th value.

Reply 535

erinls2

Original post by jaseho98

Didn't you guys found the phrasing of Q2 part 3 really weird about the "exactly 2 occurs wins draws loses". I was so stuck and I've definitely lost all my marks there lolol

Yeah I did actually - what was it? I worked out the probability of 2 wins, 2 draws or 2 losses but don't know if that's right

Reply 536

OGGUS

Do you guys think since C1 and S1 weren't majorly hard that C2 is going to be solid?

Reply 537

jn998

Original post by sqr00t

My percentages was exclusive to each data set, so I worked out a percentage for women's and a percentage for men's. Worked out women's was higher than mens

You'd get 2 out of 3, losing 1 for accuracy.

Reply 538

jaseho98

Original post by erinls2

Yeah I did actually - what was it? I worked out the probability of 2 wins, 2 draws or 2 losses but don't know if that's right

I think that you're right! Not gonna lie, a few of my friends thought the same as you. However, I just really find it stupid because it's not like we don't know how to do it... it's the damn phrasing sometimes which makes you interpret the question wrong. Then boom there goes all the marks : :smile:

) damn

Reply 539

jn998

Original post by erinls2

Yeah I did actually - what was it? I worked out the probability of 2 wins, 2 draws or 2 losses but don't know if that's right

I drew out the full tree diagram, took about 10 minutes to carefully check through the question and got 0.66. Probably wasted time doing that but I couldn't remember the method you were supposed to use