Edexcel S2 Exam Paper January 2011 14/01/11

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Reply 180

airey_head

Original post by warkan

Dude thanks so much !!! and btw the answers are correct!!! : )

Haha great! that's always good to know the day before the exam :P

Reply 181

airey_head

I wish there was some kinda page with all the definitions you have to learn on! Ugh! WHYYYYY does stats need definitions??!?!

Reply 182

atofu

i found this in the S2 cd, exam café. Doesn't have everything and there are explanations after each term but it's pretty nice

Definitions in S2
Population A population is a collection of individuals or items. Should mention it is all the items.

Sample A sample is a selection of individual members of the population. You could say it is simply a subset of the population.

Sampling Frame A sampling frame is a list of the members of the population. The key word is list.

Statistic A statistic is a random variable consisting of any function of the data that involves no other unknown population parameters.

Sampling Distribution If all possible samples are taken, then the different values of a statistic will form a probability distribution called the sampling distribution of the statistic.

Hypothesis Test A hypothesis test is a procedure for deciding between two opposing hypotheses: the null hypothesis and the alternative hypothesis.

Significance Level If the probability of a value of the test statistic being “as bad or worse” than the observed value is p, then you reject the null hypothesis if p is less than the significance level.

Critical Region The critical region is the set of values of a statistic that would cause you to reject the null hypothesis.

Conditions for…
Binomial Distribution
1. There must be a fixed number of trials.
2. The trials must be independent.
3. The trials must have only two outcomes, success or failure.
4. The probability of a success for each trial must be constant.
Remember to use the context - don’t just say trials are…

Poisson Distribution
1. Events occur independently of each other
2. Events occur singly in continuous space or time
3. Events occur at a constant rate.

Reply 183

-Iffy-

Well here's a summary of all the definitions I've got from my teacher. Some are a bit long winded though:

Definitions-
1) Population – a collection of items
2) Sampling frame – a list of items in a population, meant to contain as many items as possible, used to draw samples from
3) Census – a complete enumeration of a population
4) Random sample – a sample whose items are chosen independently and have the same distribution as the population
5) Sampling unit – an item from the population which is in the sampling frame
6) Sample – a selection of items from a population
7) Statistic – a random variable consisting of any function of the sample data that involves no other quantity
8) Sampling distribution – the distribution of a statistic, i.e. the values of the statistic based on all the possible samples
9) Hypothesis test – a hypothesis test about a parameter, tests a null hypothesis, specifying a particular value or the parameter against an alternate hypothesis, which will indicate whether the test is one-tailed or two-tailed
10) Null hypothesis – the working hypothesis, which is assumed to be true
11) Alternate hypothesis – the hypothesis that describes the situation of the null hypothesis is not true
12) Test significance – a statistic used in a hypothesis test
13) Critical region – the critical region of a test statistic is the range of values for which the null hypothesis is rejected
14) Critical values – the boundary values of the critical region

I'll just be reiterating these definitions over and over again tomorrow.

Okay i've scoured all 10 pages of this thread and still can't find the june 2010 mark scheme, did i miss it?

Reply 184

Foxer27

Got two questions:

If P(IXI<1.3) for a uniform distribution -4,6 how do you work that out and what does the modulus mean?

Also question 7a on June 2010, dont know why a is greater than 3?

Cheers

Reply 185

I smell like maths

Original post by Foxer27

Got two questions:

If P(IXI<1.3) for a uniform distribution -4,6 how do you work that out and what does the modulus mean?

Also question 7a on June 2010, dont know why a is greater than 3?

Cheers

when you sub in any x value, the outcome must be +ve. which is why is says f(3)>or equal to 0, in the mark scheme

you have to add: to stop a -ve appearing (a-y)>or equal to '0', so a>or equal to 3.

s2 exams are weird :fangs:

Reply 186

cazzy-joe

BEST OF LUCK EVERYONE

Dont do silly mistakes :biggrin:

See you all when thread is open for discussions :wink:

Reply 187

Geniusmiss

Original post by LukethePianoMan

A hypothesis test is a mathematical procedure to examine a value of a population parameter proposed by the null hypothesis H0 compared with an alternative hypothesis H1.

For a statistic, i usually say: A statistic is a random variable that is a function that contains no other values.

thanks a lot :smile:

Reply 188

Geniusmiss

Original post by cazzy-joe

BEST OF LUCK EVERYONE

Dont do silly mistakes :biggrin:

See you all when thread is open for discussions :wink:

what do u mean open for discussion? sorry im kinda new to students rooom

Reply 189

Geniusmiss

Original post by Firaila

Just did June 10 paper, found it relatively harder than the others. Would anyone else agree with this?

i do...qs.3 and qs.7a were crazy...i hope nothing like that turns up 2dy....also the grade boundaries for a* i think should have been a little bit lower

Reply 190

Geniusmiss

Original post by airey_head

Haha Thankyouuu! Better to be safe than sorry :P

Good luck! :smile:

lucky people...in my country it's in the evening what a waste of the whole day...

Reply 191

Geniusmiss

do we have to learn to work out the sampling distribution with the mean?

Reply 192

Geniusmiss

roughly how many marks out of 75 can you lose but still get an A*? i know grade boundaries change evry time but i am just asking an estimate...

Reply 193

Geniusmiss

if you hve text book i really URGE you to see example 3, 7 & 8 from chapter 5 ( pages 71-72, 75, 77)!!!! theyre really confusing please someone explain to me...and please tell me this dsnt come on the test.... :eek:

i hope this doesnt come on!!!!!! otherwise im soo dead....i really need that A*.........£$^(@$&^($%^)@

(edited 13 years ago)

Reply 194

Slowbro93

Original post by Geniusmiss

i hope this doesnt come on!!!!!! otherwise im soo dead....i really need that A*.........£$^(@$&^($%^)@

Well for the example on 71-72, its' being able to derive the variance from first principles (might go to my maths teacher to do that, as I saw it in a soloman paper)

Example on p75 is looking at error. I would just learn this, as it has come up before

The last one you said it putting what you have learnt into context.

Good luck!

Reply 195

Geniusmiss

Original post by cpdavis

Well for the example on 71-72, its' being able to derive the variance from first principles (might go to my maths teacher to do that, as I saw it in a soloman paper)

thanks for the advice...Example on p75 is looking at error. I would just learn this, as it has come up before

The last one you said it putting what you have learnt into context.

Good luck!

looking at error is page 77 riite? also how do u know which equation to use to find the the quartiles when there are multiple F(x)'s...for example page 58 in textbook, question 3

p.s. wasnt the portion harder before 2008?

(edited 13 years ago)

Reply 196

Geniusmiss

also when we have to integrate f(x) to find the median...we always use the lower limit riite?

Reply 197

Geniusmiss

any tips for pre-exam tension/nervous breakdown?? i really need an A* and I cant afford to resit! and I'm really crap at s2!!!!!! $%(!$*@(%)$*!()$*%)£*!%)_£%&!(