You are Here: Home >< Maths

# Edexcel S1 - 15th June, 2016 [Exam Discussion] watch

1. (Original post by shuu00)
What were the values for p and q
q = 0.15
p = 0.175
2. did anyone get 0.81 and 0.405 for the P(DIBnD) and P(BnD')??
3. (Original post by veldt127)
q = 0.15
p = 0.175
I got 0.22 and 0.03
4. (Original post by NickDacre)
I got 0.22 and 0.03
This is for discrete random variables. T and U were 0.03 and 0.22 for the probability question
The mean DECREASED guys, not stayed the same, we're dealing with classes here. The value of 3.43 will add one to the frequency of the 3-3.5 class. The way we work out the estimate is to multiply the midpoint of the class by the frequency. Hence, since the midpoint of this class is 3.25, which is lower than the mean, the mean decreases.
You could have also done the actual calculation to check, the mean decreased

EDIT: I'll explain this better. The mean before the added values was 3.43. Now there's an added value of 3.43. This adds one to the frequency of 3-3.5 class. In working out the value of the mean, you have to multiply mid point by frequency. Hence, you don't actually deal with 3.43 but rather 3.25, the mid point of the class. Since this value is less than 3.43 the mean decreases.
Try the calculation out for yourself and please amend the unofficial mark schemes.
But the question said 'no further calculations' so I imagine it wants you to treat the 3.43 how it is when adding to the data and not include the tables, which would keep the mean the same. I think your method, then doing the same for Standard Deviation and explaining them both would be too much for 3 marks.
6. (Original post by veldt127)
q = 0.15
p = 0.175
thanks
7. (Original post by NickDacre)
did anyone get 0.81 and 0.405 for the P(DIBnD) and P(BnD'??
I got P(D|BnD) = 0.45
P(D|BnD') = 15/37
8. The DRV question (the final bit with the E(R), etc) I got these answers (in this order)

E(r) = 0.45
Prob (whoever was the first one) = 0.475
Prob (whoever was the second one) = 0.375

I am 100% sure on these answers
9. (Original post by hogree)
Remember you did that one yesterday didn't you lol. Time is a naughty one to throw at you.

Posted from TSR Mobile
Yep!! I saw it and thought yess!! I remembered the one yesterday
10. anyone got the paper??
11. How to get 33 customers model answer!

P(D|RnB) = 0.45 and P(D|RnB') = 15/37

It says that 40 customers have rented a room and eaten breakfast
It also says that 37 have rented a room and not had breakfast

Well, we worked out the chance of them having dinner given those conditions in the two previous parts, so all we needed to do was 40*0.45 + 37 * 15/37 to come to our answer of 18+15 = 33 customers.

Hope this clears it up
12. I got P=0.1626 and Q=0.175 no idea how !! 😰😰 how many marks would I get and also would I lose marks on the rest of the question or get follow through ????
13. I have a question about the Sarah and Rebecca winnings one.

Basically how do you do it

Do they each spin individually or is it 1 spin only tat determine both of their scores if that makes sense?

Posted from TSR Mobile
14. (Original post by thelegend99)
Wahoo! Thanks for your help from yesterday as well!

How did it go for you?
That's alright. Think it was a pretty rough paper. No coding after all that revision lol. I think I've probably dropped 5-10, if I misunderstood the Sarah question. So pretty well thanks

Posted from TSR Mobile
15. (Original post by stressed16)
I got P=0.1626 and Q=0.175 no idea how !! 😰😰 how many marks would I get and also would I lose marks on the rest of the question or get follow through ????
I think you may lose a lot because maybe you'd of gained follow through had the probabilities all add up to one (which was a simple check to see you're along the right lines) but I don't think your values do
16. (Original post by iMacJack)
How to get 33 customers model answer!

P(D|RnB) = 0.45 and P(D|RnB' = 15/37

It says that 40 customers have rented a room and eaten breakfast
It also says that 37 have rented a room and not had breakfast

Well, we worked out the chance of them having dinner given those conditions in the two previous parts, so all we needed to do was 40*0.45 + 37 * 15/37 to come to our answer of 18+15 = 33 customers.

Hope this clears it up
do you remember the numbers in the venn diagram?
17. (Original post by hogree)
That's alright. Think it was a pretty rough paper. No coding after all that revision lol. I think I've probably dropped 5-10, if I misunderstood the Sarah question. So pretty well thanks

Posted from TSR Mobile
Hiw did you do Sarah question?

Posted from TSR Mobile
18. (Original post by Themathgeek)
I have a question about the Sarah and Rebecca winnings one.

Basically how do you do it

Do they each spin individually or is it 1 spin only tat determine both of their scores if that makes sense?

Posted from TSR Mobile
I dont remember my answer. I understood the question last minute. Can someone tell me if i was correct. It said a computer randomly generates their score so that means you look at the 2 charts and compare when Rachel had a higher score than the other one. Then you just add the probabilities together.
19. (Original post by Raees_Sharif)
do you remember the numbers in the venn diagram?
0.22- 0.03- 0.15- 0(on outside)
20. (Original post by Raees_Sharif)
do you remember the numbers in the venn diagram?
Unfortunately not, sorry

### Related university courses

TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Updated: August 22, 2016
Today on TSR

### Edexcel C4 Maths Unofficial Markscheme

Find out how you've done here

### 2,280

students online now

Exam discussions

### Find your exam discussion here

Poll
Useful resources

Can you help? Study help unanswered threadsStudy Help rules and posting guidelinesLaTex guide for writing equations on TSR

## Groups associated with this forum:

View associated groups

The Student Room, Get Revising and Marked by Teachers are trading names of The Student Room Group Ltd.

Register Number: 04666380 (England and Wales), VAT No. 806 8067 22 Registered Office: International House, Queens Road, Brighton, BN1 3XE