[vamos talal]

(Original post by sabreena96)
was this a calc paper or non calc?

calc

[vamos talal]

(Original post by sabreena96)
was this a calc paper or non calc?

calc

[EL77]

(Original post by vamos talal)
what grade student are you?

A*, i took this unit as a retake because when i did it june i got 107 ums and was one ums from an A*, the only reason i retook was to get an A* so i really hope i do

[EL77]

does anyone else think that this paper was harder than the other ones, like the Nov 2011 one, because the grade boundaries for the nov 2011 were 53 for an A*, so if this was harder than the grade boundary should be lower than that

[vamos talal]

(Original post by EL77)
does anyone else think that this paper was harder than the other ones, like the Nov 2011 one, because the grade boundaries for the nov 2011 were 53 for an A*, so if this was harder than the grade boundary should be lower than that

i think the same too.btw what did you write for the why his sample may be biased question?

[MrG]

Mrmanps

Your answer for question 11c is incorrect, as he doesnt just use the men aged 17-30, he uses 50 people in total only 4 of which are male and between 17-30.

A correct answer would be:

a) He only asks people in his restaurant so bias.
b) He only asks people on one evening depending on the evening he could have got different clientel so bias.
c) he only asks in the evening not during the day a lot of restaurants are open for lunch so excluding lunch time visitors would also be bias.

Other than that i got the exact same answers as you apart from the gradient where i got -0.36 but i took a triangle from 30-40 seconds and it is clearly 3.6 litres when you take the triangle up to the line p.

I think it was one of the hardest tests edexcel have given since the sample material came out so hopefully for my students the pass mark will be lower.

One other question mrmanps how have you managed to get a mark scheme already? results plus dont have it and edexcel wont release it yet, you dont happen to work for edexcel do you?

[ErinHannah]

(Original post by Matt Here)
I thought I would have got an A, but after looking at this I think i probably got a high B Oh well

Same.

[vamos talal]

(Original post by MrG)
Mrmanps

Your answer for question 11c is incorrect, as he doesnt just use the men aged 17-30, he uses 50 people in total only 4 of which are male and between 17-30.

A correct answer would be:

a) He only asks people in his restaurant so bias.
b) He only asks people on one evening depending on the evening he could have got different clientel so bias.
c) he only asks in the evening not during the day a lot of restaurants are open for lunch so excluding lunch time visitors would also be bias.

Other than that i got the exact same answers as you apart from the gradient where i got -0.36 but i took a triangle from 30-40 seconds and it is clearly 3.6 litres when you take the triangle up to the line p.

I think it was one of the hardest tests edexcel have given since the sample material came out so hopefully for my students the pass mark will be lower.

One other question mrmanps how have you managed to get a mark scheme already? results plus dont have it and edexcel wont release it yet, you dont happen to work for edexcel do you?

absolutely agree with you.in that question,we could say that he doesnt know,the number of people couldvary on weekends and weekdays.and what do you think?i worked out the probability on the last question by taking them seperately like:P(wwl)+p(wll)+p(wdd)+p(wwd) +p(www).i multiplied all of these except of p(www) by 3 but unfortunately forgot to add p(wdl)* 3 to the final answer in hurry.Do u think ill get 2 marks for this working though?

[MrG]

Yes you can do it either way and i would think that you should get 2 marks for that working and loose a mark for missing one of the probabilities out, you would get at least 1 mark anyway.

You can do it like this
P(LLL)+p(LLD)+p(LDL)+p(LDD)+p(DL L)+p(DLD)+p(DDL)+p(DDD) then take you answer away from 1. or you can work out all the probabilities that allow eric to win at least 1 game, but the modle answer at the start of the thread is by far the quickest way to do it.

[vamos talal]

(Original post by MrG)
Yes you can do it either way and i would think that you should get 2 marks for that working and loose a mark for missing one of the probabilities out, you would get at least 1 mark anyway.

You can do it like this
P(LLL)+p(LLD)+p(LDL)+p(LDD)+p(DL L)+p(DLD)+p(DDL)+p(DDD) then take you answer away from 1. or you can work out all the probabilities that allow eric to win at least 1 game, but the modle answer at the start of the thread is by far the quickest way to do it.

i thought that if u did it that way,you'd only get the probability of him winning all three.

[MrG]

No because you can get P(WLL) P(WLD) etc.

[gideongaspard]

0.673

(Original post by vamos talal)
What did you do for the last question.

[supergrantholt]

YES! After completing that paper, I was really un-confident and thought I'd get a B (I'm an A/A* student). After looking at the answer booklet, I think I've dropped a maximum of 9 marks. So I'll probably get an A. However, if my estimations are wrong and the grade boundaries are low I'm in with a shout of getting an A*!
Does anyone know the grade boundaries? Does anyone know when we get the results back?

[FitaJ3T]

Hi just to re cap on the very last question. I managed to get 783/1000. Heres what i have done:

Instead of finding the probability of finding Eric winning at least once (which will take ages!!), i decided to find the probability of him not winning at all.

We have clarified that Isobel probablity of winning one game is 0.6, so the probabilty of her winning all 3 games is 0.6 cubed (AND rule). This results in the fraction 27/125 (0.6 x 0.6 x 0.6=27/125).

We have also clarified that the probability of a draw taking place equals to 0.1 so the probabilty of drawing all 3 games is 0.1 cubed (AND rule). This results in the fraction 1/1000 (0.1 x 0.1 x 0.1=1/1000).

We will add these fractions up to give us 217/1000

We will find the inverse fraction which is 1000 - 217= 783

So 783/1000

Please tell me if i am right or wrong!!! Thank You

[vamos talal]

(Original post by FitaJ3T)
Hi just to re cap on the very last question. I managed to get 783/1000. Heres what i have done:

Instead of finding the probability of finding Eric winning at least once (which will take ages!!), i decided to find the probability of him not winning at all.

We have clarified that Isobel probablity of winning one game is 0.6, so the probabilty of her winning all 3 games is 0.6 cubed (AND rule). This results in the fraction 27/125 (0.6 x 0.6 x 0.6=27/125).

We have also clarified that the probability of a draw taking place equals to 0.1 so the probabilty of drawing all 3 games is 0.1 cubed (AND rule). This results in the fraction 1/1000 (0.1 x 0.1 x 0.1=1/1000).

We will add these fractions up to give us 217/1000

We will find the inverse fraction which is 1000 - 217= 783

So 783/1000

Please tell me if i am right or wrong!!! Thank You

It seems to a bit strange.probability of eric winning once in 0.3 not 0.6

[gideongaspard]

(Original post by vamos talal)
It seems to a bit strange.probability of eric winning once in 0.3 not 0.6

The answer was 0.673 I saw the mark scheme its on this thread ( i got it right too yay me!)

[gideongaspard]

after looking at the mark scheme I'm really confident I got an A* I only dropped 3 marks please god make the examiner give me an A*!!!!

[mrmanps]

(Original post by MrG)
Mrmanps

Your answer for question 11c is incorrect, as he doesnt just use the men aged 17-30, he uses 50 people in total only 4 of which are male and between 17-30.

A correct answer would be:

a) He only asks people in his restaurant so bias.
b) He only asks people on one evening depending on the evening he could have got different clientel so bias.
c) he only asks in the evening not during the day a lot of restaurants are open for lunch so excluding lunch time visitors would also be bias.

Other than that i got the exact same answers as you apart from the gradient where i got -0.36 but i took a triangle from 30-40 seconds and it is clearly 3.6 litres when you take the triangle up to the line p.

I think it was one of the hardest tests edexcel have given since the sample material came out so hopefully for my students the pass mark will be lower.

One other question mrmanps how have you managed to get a mark scheme already? results plus dont have it and edexcel wont release it yet, you dont happen to work for edexcel do you?

I agree with what you said about the bias question. I really ought to read the questions properly.
MS wont be released for a short while. I have a provisional one.

[FitaJ3T]

(Original post by vamos talal)
It seems to a bit strange.probability of eric winning once in 0.3 not 0.6

HI, I understand Eric winning a single game= 0.3, Isobel winning =0.6, draw= 0.1 (Total = 1), all i did was figure out the inverse fraction ((0.6x0.6x0.6)+(0.1x0.1x0.1)) since it was the easiest and less time consuming and then i reversed it to find the actual answer. Looking at the unofficial mark scheme, the did 0.7 to the power of 3. I dont know why they did that!! Did they add 0.1 to 0.6?? (Isobel+Draw). If they did, why?? Is it right??(after all it is unofficial).

[MrG]

They did that because its the probability that Eric looses OR Draws a game (ie doesnt win) if you cube this you get the probability that Eric Doesnt win a game in three trys so taking this away from 1 would leave you with the probability he wins at least 1.

Where you went wrong is you assumed win win win was the only option however the questions states he wins at LEAST 1 game so he could win 1 game 2 games or all 3, so theres a huge amount of combinations.

for example:

WWW
WWD
WWL
WDW
WDD
WDL
WLW
WLD
WLL
DWW
DWD
DWL
DDW
DLW
LWW
LWD
LWL
LDW
LLW

If you worked out all these probabilities and added them together you would get the same answer thats on the mark scheme. BUT its very easy to miss one out.