Edexcel S2 Exam Paper January 2011 14/01/11

After checking up the solutions, I feel Minimum marks is 69(This is the worst case scenario where I lose all the 5 marks for Uniform and 1 mark to show the f(x) is 4-8x, because my method was partly different from the MS posted here)
Maximum marks is 71 or 72(This is where I get the f(x) part right and 1/5 or 2/5 for the uniform)

So 69--72 / 75.. :smile:

...Hoping for +90UMS

Reply 401

olly1973

Original post by Gibbo81

Question 1

Should one of the assumptions be that there are only 2 possible outcomes to be considered binomial distribution?

Reply 402

Slowbro93

OP

20

There was a question on 7 when it said to work out the probability of the amount of people who waited for more then 5 minutes. It said use integration to find it, but I did it differently. I used integration to work out F(x) and then I substituted for x. I got all the same answers and everything, just worked it out differently with the same concept. Will I get the marks?

Reply 403

Slowbro93

OP

20

Original post by Gibbo81

Question 1

Thanks! I agree with all your answers, and from the looks of it, I have full marks :woo:

Reply 404

jit987

13

Original post by cpdavis

There was a question on 7 when it said to work out the probability of the amount of people who waited for more then 5 minutes. It said use integration to find it, but I did it differently. I used integration to work out F(x) and then I substituted for x. I got all the same answers and everything, just worked it out differently with the same concept. Will I get the marks?

You should get the marks if you have atleast used some integration.

Reply 405

snowflakesblues

1

Original post by Spongy

Sorry to post this again but on question 5(a) would you still get marks for integrating the f(x) between the limits of 0.5 and 0 and showing that the area under the curve is equal to one (which is a condition of a p.d.f.)

I think yours is the most relevant way of doing it. because it shows that the p.d.f is valid for that range. So I don't see why u wont get the marks.

Reply 406

Firaila

9

Original post by Spongy

Sorry to post this again but on question 5(a) would you still get marks for integrating the f(x) between the limits of 0.5 and 0 and showing that the area under the curve is equal to one (which is a condition of a p.d.f.)

I dont see why not :smile:

Reply 407

sete

Could someone please explain to me why, for the last question why the distribution is B ¬ (3 , 0.478) where did the n = 3 come from?

Other than that pretty good few silly mistakes 65 + with harsh marking.

1, a) Think i forgot to state n is fixed number of terms DUH! 1 mark
5, C) Didn't say the 0.868 value was outside range =/ 1 mark
6, d) pretty sure i got that wrong. Lose 3 marks if wrong (maybe a mark or 2 for method)
7, b and c) Working was abit scruffy but got the right answers. Might lose 2 marks
7, d) For some reason i approximated and used a poisson lulz! Lost 3 marks

Probably a low A depending on boundaries.
Thanks for the solutions btw. :smile:

Reply 408

Slowbro93

OP

20

Original post by jit987

You should get the marks if you have atleast used some integration.

Thank you!!! This has put my mind to rest! Now going to focus on dreaded Physics, going to try and avoid going on TSR this weekend :yep:

Reply 409

Spongy

Original post by snowflakesblues

I think yours is the most relevant way of doing it. because it shows that the p.d.f is valid for that range. So I don't see why u wont get the marks.

Cheers for that, if you look at more recent mark schemes they always seem to show a range of methods - each getting some credit for.

If I get the marks for 5(a) I will be getting 73 out of 75 so I am happy.

Reply 410

partyabitmore

Original post by Spongy

Sorry to post this again but on question 5(a) would you still get marks for integrating the f(x) between the limits of 0.5 and 0 and showing that the area under the curve is equal to one (which is a condition of a p.d.f.)

I did the exact same thing, so I really hope it is the right way.

Reply 411

sete

Original post by dolly88

i haven't read every-ones posts so sorry if this has already been asked...
but did anyone do poisson on the very last question?

i got something like .4779 as the probability, then multiplied by 3, to get x~Po(1.5ish) then used this....??

Yeah i did this too!! I couldn't work out how 3 was the number of terms. So thought it had to be a Poisson.

Reply 412

EnVogue

13

So are we thinking the grade boundaries are going to be pretty high?

In the last question it said:

"Three independent customers" so binomial (3, 0.whatever)

Reply 413

snowflakesblues

1

Original post by Spongy

Cheers for that, if you look at more recent mark schemes they always seem to show a range of methods - each getting some credit for.

If I get the marks for 5(a) I will be getting 73 out of 75 so I am happy.

I think I lost 3 marks in total lol, so far. If I get an A* I will be over the moon, If an A that's okay I guess. I really don't know what to expect, I'm like a machine for making errors in exam conditions xD In my previous C3 exam, I came out thinking I got at least 90, but I got a C...so yeah...any A will do I guess xD Fingers crossed :biggrin:

Reply 414

aneesh

I doubt i have any time left to do 3 more modules
so my mathematics is c 1-4 and S1 FP1
and my further maths is s2 s3 fp3 ?

Thanks for all the help :smile:

Reply 415

snowflakesblues

1

Original post by EnVogue

So are we thinking the grade boundaries are going to be pretty high?

In the last question it said:

"Three independent customers" so binomial (3, 0.whatever)

From the looks of things, I have a feeling they might be pretty high. And maybe 63/65 for an A.

Reply 416

abcdefpd2001

7

Question 2 in the unofficial markscheme : there is not enough evidence to say that she is guessing.... if I said there is enough evidence to say that she is cheating and the teacher's claim is right, is it the same thing????

Reply 417

sete

Original post by EnVogue

So are we thinking the grade boundaries are going to be pretty high?

In the last question it said:

"Three independent customers" so binomial (3, 0.whatever)

Thanks. I can see my failure now.

Reply 418

Firaila

9

Original post by sete

Yeah i did this too!! I couldn't work out how 3 was the number of terms. So thought it had to be a Poisson.

3 was the number of terms because the question said there were 3 people

Reply 419

snowflakesblues

1

Original post by aneesh

I doubt i have any time left to do 3 more modules
so my mathematics is c 1-4 and S1 FP1
and my further maths is s2 s3 fp3 ?

Thanks for all the help :smile:

Yep ye. FM can come from FP2 , S2, S3. And you get an extra A2 hanging in there. I guess your teacher probably made you do more so you can shuffle the grades around :smile:

Edexcel S2 Exam Paper January 2011 14/01/11

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