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# OCR MEI D1 15th June & M1 17th June 2016

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1. (Original post by lilrabbits)
How did you get that? Thanks!
7 gave p as like 0.4 something , 6 was 0.5 something so less than 7
2. (Original post by ineedA)
7 gave p as like 0.4 something , 6 was 0.5 something so less than 7
yea but the algorithm said take the first value of n for which p is less than 0.5
3. (Original post by lilrabbits)
For the simulation question, how would you interpret the results? It worth like 3 marks.
what I did was ....there were 3 win 2 loss, 5 altogether 3/5 0.6, probability 0.6 2/5 0.4
4. (Original post by StrangeBanana)
yea but the algorithm said take the first value of n for which p is less than 0.5
it's definitely less than 7, I might be wrong but that's what all my friends got, I can't remember the q exactly /:
5. (Original post by ineedA)
it's definitely less than 7, I might be wrong but that's what all my friends got, I can't remember the q exactly /:
Dont think its less than 7. IIRC the algorithm was to find how many cards youd need to draw to have > 0.5 prob of drawing the same one twice? So if anything itd be 7 or more
6. That paper has literally ensured I'm not going uni, there's no way I can get an A now, even with 260 ums from last year. Couldnt do the majority of the linear programming and got a total time of 14 for the activity on arc diagram
7. D1 ? I'll give MEI the D in a minute...

8. (Original post by ineedA)
it's definitely less than 7, I might be wrong but that's what all my friends got, I can't remember the q exactly /:
You were finding the least number of cards you had to draw to have a 0.5 chance that two of them were the same, and there were 26 cards. You can do it with S1 probability:

Probability none are the Same with 7 cards = 1x(25/26)x(24/26)x(23/26)x(22/26)x(21/26)x(20/26) = 0.413
Probability none are the same with 6 cards = 1x(25/26)x(24/26)x(23/26)x(22/26)x(21/26) = 0.537

So the probability two are the same with 7 cards drawn is 1 - 0.413 = 0.587, but with 6 cards it's only 1 - 0.537 = 0.463. So you need 7 cards.
9. (Original post by StrangeBanana)
x
https://youtu.be/cXKy_Bop0FQ
That paper has literally ensured I'm not going uni, there's no way I can get an A now, even with 260 ums from last year. Couldnt do the majority of the linear programming and got a total time of 14 for the activity on arc diagram
you might be okay, you only need 220 ums this year so as long as you got more than 20 ums in D1 it's possible
11. (Original post by Jamesinatr)
x=10, y=0, z=10 anyone?
I got exactly that, seems quite reasonable too, since y had a lot of wastage makes sense to avoid it.
12. Does anyone have the topic assessment answers for the MEI website?
13. The worst paper I've ever ****ing sat! And I wanted 100%...be lucky to scrape a C now
14. It was 6
n=n+1 so although when trying to find out p you'd have been using 7 for the equation, you only had to select 6 cards for the probability to less than 0.5
15. Did you all get 48 for dijkstras ? Me and a few of my friends did but a couple got 49/50
16. For the LP question I'm pretty sure when it said use the second plan with 32 cuts it meant the one you'd just created which is labelled z. Then for when they say that X>=20 that because it's cut into two pieces you have to interpret it as x>=10 and then there's three cuts for the 32cm one so Y>=26 becomes y>=8 then the sum must equal 20 and since we've eliminated the plan where you do 1x47cm 1x32cm that means x+y=20 I then plotted these on the graph and then minimised the waste. Idk if that's right but that's how I'd interpreted the poorly worded question that was that LP
17. (Original post by bethygirl)
Did you all get 48 for dijkstras ? Me and a few of my friends did but a couple got 49/50
I got 48, I can see where they got 49 but there was another route to get 48
18. (Original post by gemlowe)
I got 48, I can see where they got 49 but there was another route to get 48
Yep the penultimate step (I think) turned it from 49 to 48
19. Holy ****, that paper...

How many dummies did people get on the activity network? I got 5 or 6 first time, redrew it and got 3...
20. (Original post by Mostly_Crazy)
Holy ****, that paper...

How many dummies did people get on the activity network? I got 5 or 6 first time, redrew it and got 3...
I think I ended up with 2

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Updated: June 17, 2016
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