D1 ocr mei june 2011

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HI im so confused

can someone help me

if you have a question regarding simulations

it says 1/4 chance of turning left and 3/4 chance of turning right

00-24 -->left and 25-99 --> right

00-74 -->right and 75-99 --> left

are both valid solutions however as the random numbers are set
only one of them will be right

how do i know which to use ???

Original post by ben10

also on jan 2008 question 4 part 3 where you have to carry the simulation out i dont understand why the second offspring has brown eyes because brown and blue parents hav 50% brown chance and 50% blue chance so random numbers will be
0-4 = brown and 5-9 = blue so when given random number 9 isnt it meant to be blue coloured eye . please explain or have i allocated the numbers wrongly ?

I hope this will answer both your questions.
Obviously, there are many different simulations that are possible.

If yours isn't what is on the mark scheme,. but is still accurate, you will get marks, and they will check your simulations to make sure you've followed through with what you said.

Is that okay? Or have I not explained?

Reply 21

mqt

Original post by AmiB

I'm sitting this one on wednesday too, I just went through every section test on the integral resources online then I am going through every past paper, marking it myself and then reading the examiners report. I find that marking it myself and reading the examiners report is really useful because you learn what the examiners want you to put for certain questions that they always seem to ask.

Been getting A's so far in the past papers so hopefully it will run true for the exam. I've only got one past paper left now and I'm just about to do it so I don't know what I will do from now until wednesday haha just have to keep looking over the syllabus to remind myself of everything.

The only thing I struggle with is the different types of floats in CPA, I can never remember which is which and how to calculate them. Anyone else find this?

OMg! i'm finding d1 really really difficult! i'm not getting anymore than 70%... and i desperately wnat like 90% cause i'm so worried that my c4 went so badly! ....i've had a's in c1,c2,c3 and s1...but seriously..c4..i made so many mistakes! pls help?!...
i'm taking froever to actually UNDERSTAND the questions..thats the worse bit...otherwise if someone told me do this and this..i'd be fine lol...:P...well yeh..probably be the same for everyone...do this and this, and everyone would be able to do it hhaaha :P
but seriously..pls help! :colondollar:

Reply 22

mqt

Original post by MHRed

I've never done them?
Are they like video lessons, or what? :smile:

I've been doing past papers, like I say, and it really does seem a case of being able to do Simulation, Linear Programming and CPA + understanding graphs.
Definately get 95% plus :smile:

Whats CPA?... any tips on undertsanding graphs? lol

Reply 23

MHRed

Original post by mqt

Whats CPA?... any tips on undertsanding graphs? lol

Critical Path Analysis.

What is it that you struggle with in particular, is it drawing the graphs? (for Linear Programming)

EDIT: Sorry, I'm confusing myself.
Is it Graph theory or the graphical linear programming you're having trouble with? :smile:

(edited 12 years ago)

Reply 24

mqt

Original post by MHRed

Oh haha, yeh i shouldve made that more specific..i'm having trouble at both infact! :/ lol... firstly..i'm finding it hard what to shade..and how to actually make the constraints...
and graph theory..i just don't ever seem to understand what they're asking :frown:

thanks in advance by the way! :h:

Reply 25

MHRed

Original post by mqt

thanks in advance by the way! :h:

I'm not great with graph theory, but it's just a case of learning all the vocab and practise.

My suggestion would be to try possible values of x and y to see which one is the right side.
i.e. if you had a line like x + y > 10.
I would think if I went really close to the origin, would the above line be true (so let's say they both = 1). Obviously this isn't true, as it = 2, so I would shade the region below it, because the region is above.

Does that make any sense? :smile:

Constraints I've never really had a problem with, so it's hard to give advice :frown:

And my pleasure :smile:

(edited 12 years ago)

Reply 26

Saffcake

I'm quite worried about d1 since I've not even started revising due to having loads of other exams...hopefully tonight and tomorrow will leave me enough time!

Reply 27

mqt

Original post by MHRed

Constraints I've never really had a problem with, so it's hard to give advice :frown:

And my pleasure :smile:

actually that was really useful! Lol! :smile:

...i'm trying to start learning vocab and practiving... but i did a jan 2010 paper today..was REALLY difficult..well...i'm exaggerating but it was relatively hard lol

Reply 28

MHRed

Original post by mqt

actually that was really useful! Lol! :smile:

...i'm trying to start learning vocab and practiving... but i did a jan 2010 paper today..was REALLY difficult..well...i'm exaggerating but it was relatively hard lol

I'm glad to be of assistance :smile:

The more papers I've do, the more worried I get :frown:

Did one earlier and just didn't have a clue D:
Let me know how you get on! :smile:

Reply 29

tooosh

Trollolololol I just learnt critical path analysis. Gotta finish messing around with resource histograms, then Physics 4, tomorrow will be S2 revision and learning Linear Prog+Simulation. Cutting it close to say the least :s-smilie:

Whoever said you can just no-life it and learn D1 2 days before the exam and understand most of it was right. Even if it means you don't get much practice but oh well.

Reply 30

DymentriX

So then, who thinks they are ready?

Reply 31

mqt

Original post by MHRed

I'm glad to be of assistance :smile:

The more papers I've do, the more worried I get :frown:

Did one earlier and just didn't have a clue D:
Let me know how you get on! :smile:

I think that i just need to cram cram cram practice...cause im not doing too badly now..and i just need to learn to READ the question...cause with c1-c4 and s1..it was eas to skim read a question and be able to ace it still

Reply 32

MHRed

Original post by DymentriX

So then, who thinks they are ready?

Not great, but not bad.
I wish we had a proper teacher/spent more time on it, but the key concepts are okay and they are worth a lot.

What's everyone hoping the harder/big questions are on?
I'd like to have a juicy simulation one, or LP. Anything but a big Critical Path Analysis/Cascade question :tongue:

Reply 33

tooosh

Original post by MHRed

I'd like to have a juicy simulation one, or LP. Anything but a big Critical Path Analysis/Cascade question :tongue:

My thoughts exactly.

One question, are the only simulations you have to deal with random number ones?

Reply 34

ben10

Original post by MHRed

can you help me out with the simulation question on june 2008 actually running the simulation dont get it at all

Reply 35

Liquify_The_Sky

I'm sitting D1 tomorrow and at the moment I'm probably going to end up with a C on this paper :s-smilie:

I'm really struggling with crashing networks! And the whole 'resource levelling' thing! Any advice please...

Also I'm looking at June 2010 and I'm stuck on question 6 part iii) and iv) :confused:

Reply 36

Liquify_The_Sky

Original post by MHRed

I'd love a simulation question. Or even better - Kruscals, primms or djkstra :smile:

Not so hot on cascade diagrams though. And if we get given an algorithm I hope it's something really concise, not with about a million steps or anything :smile:

Reply 37

brobro

Original post by tooosh

My thoughts exactly.

One question, are the only simulations you have to deal with random number ones?

yes. Only random number simulations will come up as that is what they think is the hardest

Reply 38

DymentriX

Original post by Liquify_The_Sky

I'm sitting D1 tomorrow and at the moment I'm probably going to end up with a C on this paper :s-smilie:

I'm really struggling with crashing networks! And the whole 'resource levelling' thing! Any advice please...

Also I'm looking at June 2010 and I'm stuck on question 6 part iii) and iv) :confused:

Always look at crashing the critical activities as they will have the most effect. But you must be careful of how much you crash them by as another activity may become critical.

Reply 39

Degreen

One last tip:

Stay calm during the exam. So often have I been frustrated at a question, such as the one on the past paper where it asks you to calculate the date of Easter Sunday. I spend lots of time on it without reaching an answer.

If this happens, just calm down and start again; in the example above I got it first try when re-trying, and still managed to finish the paper in 1 hour.

I average around 35 minutes for papers now :smile: