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Edexcel Mathematics: S1 6683 7th June 2017 [Exam Discussion]

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Reply 180

14buzz20

The probabilities for X^2 are the same as X. The only difference is you square the X values.

1,4,9,16

Reply 181

jsd26

Original post by Exams421

Resits are available next year but won't be again after that.

Thank you, I just found a link which states it is until 2019 if anyone else is wondering.
https://www.gov.uk/guidance/timings-for-the-withdrawal-of-legacy-gcses-as-and-a-levels

Reply 182

14buzz20

That question 6 is literally the hardest question I've seen. You gotta realise x is P(Faulty|Not passed), they give you P(Not passed|Faulty)=0.03%.

From memory, that's how I remember it.

Reply 183

Mainline421

Original post by jsd26

Thank you, I just found a link which states it is until 2019 if anyone else is wondering.
https://www.gov.uk/guidance/timings-for-the-withdrawal-of-legacy-gcses-as-and-a-levels

Guess I was wrong then, I thought 2019 was only for A2 units, but having just quickly checked it appears that is not the case. There probably won't be much competition for AS units in 2019 though!

Reply 184

Luke7456

Original post by Exams421

Guess I was wrong then, I thought 2019 was only for A2 units, but having just quickly checked it appears that is not the case. There probably won't be much competition for AS units in 2019 though!

2018 is the lasts chance for first sits 2019 is he last chance for resits so you can only sit modules in 2019 which you have already sat before.

This won't be much use to me because I probably go to uni this year but if I don't I will certainly be going next year. So won't be doing resits in 2019 I mean unless it gets silly e.g. Like I have A*A*B and their is just one module to worry about which can turn to A*A*A* for cv but then it would have to not clash with any first year uni exams and still would seem pointless

Reply 185

Keira Larkin

Original post by ryandaniels2015

So for example in the second pic would the top line not be 0.65 * 0.35?

what value are you trying to find out?

Reply 186

Keira Larkin

Original post by ryandaniels2015

Hi, Just struggling with some probability content,

I know in a venn diagram A n B is the probability when they intersect
and in a tree diagram is it probability of one branch * the other branch

But is Probability of A n B = P(A) * P(B)? I've always learnt from GCSE that n is AND meaning * and U is OR meaning + does this not work anymore?

The rule: A n B = P(A) * P(B) only works when the events are independent.
If they are dependent, A n B = P(AIB) * P (B)
If they are mutually exclusive, A n B is always equal to 0

I suggest you look up these rules on http://examsolutions.net
He explains it very well

Reply 187

Keira Larkin

Original post by Florent venhari

Hi people,

How do you do the whole of part (f) to question 2 in the JUNE 2016 paper about Rebecca and Sarah winning?

Draw probability distribution tables for variables S and R
Find out the values of x for which S is greater than R for part i) and add the corresponding probabilities together
Do something similar for part ii)

Reply 188

Keira Larkin

Original post by 14buzz20

That question 6 is literally the hardest question I've seen. You gotta realise x is P(Faulty|Not passed), they give you P(Not passed|Faulty)=0.03%.

From memory, that's how I remember it.

Which question is this? I'd like to try it out

Reply 189

14buzz20

Delphis Paper 5 Q6 part b

Reply 190

14buzz20

Also if P(A|B)=P(A),

Events are independent.

This knowledge was required on the Oct 2016 IAL paper

Reply 191

ryandaniels2015

Hi, In normal distribution when you don't have an exact value for Ф(z)
do you select the nearest value to find z?

Reply 192

Apachai Hopachai

Original post by ryandaniels2015

Hi, In normal distribution when you don't have an exact value for Ф(z)
do you select the nearest value to find z?

Reply 193

ryandaniels2015

Original post by Apachai Hopachai

Thanks does anybody have an example showing this?

Reply 194

Qer

Need help in this question

Reply 195

candol

Original post by Qer

Need help in this question

This is a discrete uniform distribution (like rolling a fair dice).
E(x) is (1 + n)/2
So 10 = (1+n)/2
20 = 1 + n
So n is 19
Does this help?

Reply 196

Qer

Original post by candol

This is a discrete uniform distribution (like rolling a fair dice).
E(x) is (1 + n)/2
So 10 = (1+n)/2
20 = 1 + n
So n is 19
Does this help?

How you got E (x)=1+n/2

Reply 197

candol

Original post by Qer

How you got E (x)=1+n/2

Its a result that is true for the discrete uniform distribution.
e.g if you roll a dice you may get 1, 2 ,3, 4, 5, or 6
Adding up the first and last term and then dividing by 2 gives the expected outcome (of 3.5 in the case of a dice). Handy to know