OCR MEI - S1 - 20th May 2015

Is this right for the last question?

1 - [ (14/20 × 13/19 × 12/18) + (6/20 × 14/19 × 13/18) + (6/20 × 5/19 × 14/18) ]

= 0.459649123 = 0.4596 (4 sig figs)

I just put 6/20 * 5/19 = 3/38 = ...... (4.s.f) (can't remember it)

Because I just saw it as P(fail then fail)

Reply 361

username1421435

17

In general how did everyone find the exam, and what do they think the grade boundaries will be relative to previous years? & how many for full UMS etc

Reply 362

ComputerMaths97

17

Original post by Eux

In general how did everyone find the exam, and what do they think the grade boundaries will be relative to previous years? & how many for full UMS etc

I think very similar to last year, has to be >=71/72 for full UMS (not too many trick questions). How did you find it? What you hoping for? I found it relatively easy, 72/72 is still a possibility I think for me :smile:

Reply 363

username1421435

17

Original post by joe12345marc

I think very similar to last year, has to be >=71/72 for full UMS (not too many trick questions). How did you find it? What you hoping for? I found it relatively easy, 72/72 is still a possibility I think for me :smile:

Agreed, though I left it quite fine with one of the questions regarding time. Some of the probability questions required me to look back at them once I had finished checking but I think they should be correct.

Reply 364

MathsMaestro

Original post by Eux

In general how did everyone find the exam, and what do they think the grade boundaries will be relative to previous years? & how many for full UMS etc

Last year for S1 the grade boundary for an A was 61/72. This years paper was quite easy so grade boundaries could be high. My guess is 65/72 for an A this year

Reply 365

liverpool2044

10

Original post by MathsMaestro

Is this right for the last question?

1 - [ (14/20 × 13/19 × 12/18) + (6/20 × 14/19 × 13/18) + (6/20 × 5/19 × 14/18) ]

= 0.459649123 = 0.4596 (4 sig figs)

yeah i got this

Reply 366

Lewart

Original post by MathsMaestro

Last year for S1 the grade boundary for an A was 61/72. This years paper was quite easy so grade boundaries could be high. My guess is 65/72 for an A this year

There's not a chance it will be 65

Reply 367

username1421435

17

Original post by MathsMaestro

Last year for S1 the grade boundary for an A was 61/72. This years paper was quite easy so grade boundaries could be high. My guess is 65/72 for an A this year

Original post by Lewart

There's not a chance it will be 65

Agreed, 90% raw is pretty unheard of

Reply 368

LilJon

2

Original post by MathsMaestro

Last year for S1 the grade boundary for an A was 61/72. This years paper was quite easy so grade boundaries could be high. My guess is 65/72 for an A this year

last years was so much easier than this year, the hypothesis test will probably have stumped people as you couldnt use the tables, so no way it will be 65 for an A when last years was 61. Talking out your arse lad

Reply 369

Studious_Student

10

Original post by Duskstar

Yes, definitely. My teacher told us specifically to answer in terms of H0, because you haven't taken any steps to prove the validity of H1, so the only way you can answer with absolute certainty is with relation to H0.

Ahh. Thank you for the confirmation and clarification! For the second part I said it in both ways from H(o) and H(1) just to be safe! :biggrin:

Hoping that method marks from the last questions save me and give me a high UMS mark for this!

Posted from TSR Mobile

Reply 370

adrianblazesit

5

Original post by Setarehp

Thanks! what about a B?

I'm guessing it'll be 7-8 marks between each grade boundary, maybe 52-54?

Reply 371

adrianblazesit

5

For the last question, I said his child didn't pick any sweets because he went and got baked instead :frown:

hoping i'll get 4/20 overall

Reply 372

DashDotDotDash

2

Original post by yoomi

1) http://furthermaths.org.uk/mei-revision
2) http://www.examsolutions.net/maths-revision/syllabuses/MEI/period-1/S1/module.php

thank you ^^ (Sorry for the late reply,)
Those videos will be useful for my other exams aas well, Thank you u w u

Reply 373

MathsMaestro

Hypothesis test:

X~B(20, p)
p is the probability that a random person in the population will be treated for a minor illness.

H0 : p = 0.78
H1 : p > 0.78

H1 has this form because researchers hope that the new drug will treat a higher percentage of people than the old drug (something like that can't remember exactly what the context was)

P(X>=19) = 1 - P(X<=18) = 0.046145272 = 0.0461 (3sf)

0.0461 > 1%

So not significant. We cannot reject the null hypothesis. We can conclude that there is not sufficient evidence to suggest that the new drug is more effective than the old drug.

( This is what I got and may be the correct answer. Unfortunately, the formula book only had the probabilities 0.75 and 0.8. To get the accurate value Bcd had to be used on the calculator in Stat mode or Math mode with x set to 18, numtrial set to 20 and p set to 0.78. You then do 1 - the answer to get the probability of P(X>=19) )

Reply 374

jpetersgill

2

Original post by adrianblazesit

For the last question, I said his child didn't pick any sweets because he went and got baked instead :frown:

hoping i'll get 4/20 overall

Nabeel mate

Posted from TSR Mobile

Reply 375

jpetersgill

2

Original post by MathsMaestro

Hypothesis test:

X~B(20, p)
p is the probability that a random person in the population will be treated for a minor illness.

H0 : p = 0.78
H1 : p > 0.78

H1 has this form because researchers hope that the new drug will treat a higher percentage of people than the old drug (something like that can't remember exactly what the context was)

P(X>=19) = 1 - P(X<=18) = 0.046145272 = 0.0461 (3sf)

0.0461 > 1%

So not significant. We cannot reject the null hypothesis. We can conclude that there is not sufficient evidence to suggest that the new drug is more effective than the old drug.

( This is what I got and may be the correct answer. Unfortunately, the formula book only had the probabilities 0.75 and 0.8. To get the accurate value Bcd had to be used on the calculator in Stat mode or Math mode with x set to 18, numtrial set to 20 and p set to 0.78. You then do 1 - the answer to get the probability of P(X>=19) )