**HL Maths P2 Before/After

finality

Dapics wrote: »

Causility does not imply correalation....

Actually it does, if one variable causes a change in the other there will be a correlation between the two, you've got that backwards.

The shape of the data is in such a direction.
In 2009, there was no correlation, also there was no causility.

in 2011, there was a positive LINEAR relationship between interest rates and precentage of population.

Causility implies there has been an increase in the amount of people in arrears AND the increase in interest rates as a subsequent result.

The emphasis is that as interest rates increased, it was harder for people to repay mortgage, therefore amount of people unable to pay mortgage increased from 2009-2011.

The direction of the causility is the outward movement of the linear relationship.

Thats the way I argued it.

The direction of causality means which increase causes which. That is, does the percentage of people in appears cause an increase in interest rates, or does an increase in interest rates cause an increase in the percentage of people in arrears. I'm almost certain that's the answer.

gethepoints

So how many marks is going for that hypothesis test question? 50 would you say? (For question 7 part a it had 5 short questions which i assume is going for 5 marks each at a total of 25.)

finality

gethepoints wrote: »

So how many marks is going for that hypothesis test question? 50 would you say? (For question 7 part a it had 5 short questions which i assume is going for 5 marks each at a total of 25.)

God I sincerely doubt they'd give 50 marks for any one question. More likely 10 for each short question and 25 for the hypothesis test.

sdiff

Dapics wrote: »

Causility does not imply correalation....

The shape of the data is in such a direction.
In 2009, there was no correlation, also there was no causility.

in 2011, there was a positive LINEAR relationship between interest rates and precentage of population.

Causility implies there has been an increase in the amount of people in arrears AND the increase in interest rates as a subsequent result.

The emphasis is that as interest rates increased, it was harder for people to repay mortgage, therefore amount of people unable to pay mortgage increased from 2009-2011.

The direction of the causility is the outward movement of the linear relationship.

Thats the way I argued it.

But they are not asking what the direction of causality is. They are asking what "direction of causality" meant. There was no need to reference to the question.

Incidentally the two factors may not even have a causal relationship, but simply a correlation caused by a third factor, namely economic circumstances of the household in question. Obviously they weren't asking anything of the sort.

Togepi

Did anyone get 62 for the first part of question 5? (The one with the batteries.)

cocopopsxx

Togepi wrote: »

Did anyone get 62 for the first part of question 5? (The one with the batteries.)

Yes, i did and a few others I know did too.

WestIRL

sdiff

Togepi wrote: »

Did anyone get 62 for the first part of question 5? (The one with the batteries.)

That is half the answer of 124 which is the most common answer (the mode!).

This suggests to me that you only took the values for one side of the mean, I.e only those that were too small or only those that were too big.

Dapics

finality wrote: »

Actually it does, if one variable causes a change in the other there will be a correlation between the two, you've got that backwards.



The direction of causality means which increase causes which. That is, does the percentage of people in appears cause an increase in interest rates, or does an increase in interest rates cause an increase in the percentage of people in arrears. I'm almost certain that's the answer.

I beg to differ.

I realise i wrote it backwards there.
Yet I would think you get my argument for it.

The word "direction" is key to that question. If you understand causility, you would know that its direction is the movement of the linear relationship between interest rates and percentage of pop.

Ah well, we will see when the marking schemes come out.

nemokath

Akanthia wrote: »

Did anyone notice a serious disconnect between sample papers given and the one we receieved? i thoght the circle question was unreasonable in the time given and after i read the papagraph on arrears and the questions i cried. i lef question 7 and 8 almost blank loosing 150 marks and the A i was hoping for {and got in the mocks}. so because of project maths and the time i spent learing it over my other subjectsim gonna loose a year of my life.


SEC- paper 2 was chernobyl.

when i repeat and make money i will duely sue you:D:D:D:D

Have to completely agree, I was hoping for an A as well but reckon I've completely lost it now. My question 8 was almost entirely blank, even if they tired to give me marks I highly doubt they could :P I was so cross with project maths.

Togepi

sdiff wrote: »

That is half the answer of 124 which is the most common answer (the mode!).

This suggests to me that you only took the values for one side of the mean, I.e only those that were too small or only those that were too big.

I have no idea what I was doing. I barely revised that section, and I was probably better off not looking over it anyway 'cause the formula probably would've just confused me.

John Mullally

gethepoints wrote: »

So how many marks is going for that hypothesis test question? 50 would you say? (For question 7 part a it had 5 short questions which i assume is going for 5 marks each at a total of 25.)

How do you actually prove the hypothesis question. Can some please do a rough solution. No any one part of a question is worth more than 25marks so its hardly 50marks.

sdiff

Dapics wrote: »

I beg to differ.

I realise i wrote it backwards there.
Yet I would think you get my argument for it.

The word "direction" is key to that question. If you understand causility, you would know that its direction is the movement of the linear relationship between interest rates and percentage of pop.

Ah well, we will see when the marking schemes come out.

What do you mean by "movement of the linear relationship"

gethepoints

John Mullally wrote: »

How do you actually prove the hypothesis question. Can some please do a rough solution. No any one part of a question is worth more than 25marks so its hardly 50marks.

Sorry, I meant that whole question about the properties. I forgot there were a few other small ones. They were easy probability questions that's why.

Hermione Granger

sdiff wrote: »

I got the same for the first bit (124 batteries).
I'm not sure where you're getting the second bit from. The range is still 20.25 and 19.75. Standardising gave us (20.25-20.05/0.1) and (19.75-20.05/0.1).
If it were 95% (ie 2 standard deviations) it would have to be 0.2 either side of 20, I.e from 19.8 to 20.2

Got something very similar got 124 batteries as well on the top which is equal to .0124 or 1.24 %

Then for the second bit I got .0668 and .0662 which adds to give .133 or 13.3%

Then 13.3% -1.24% = 12.06 % Anyone agree ???

I did all three sets of exam papers edco folens and educate.ie in school between november and june and I have to say the educate.ie ones were excellent for these kind of probability ones

jonny tightlipps

RedTexan wrote: »

That's a question for an economist, not a leaving cert maths exam. I'd hope going on about how high interest rates were corresponding with the high % of arrears would get me there. There were some terribly worded question ie. thh percentage increase? I said 94% but it would appear I was wrong, still should get the majority of marks there though for showing the amount of batteries and that

you are a batty boy.

Hermione Granger

John Mullally wrote: »

How do you actually prove the hypothesis question. Can some please do a rough solution. No any one part of a question is worth more than 25marks so its hardly 50marks.

The study described in part [FONT=TimesNewRoman,Bold](d) [/FONT]was so large that it can be assumed to represent the
population. Suppose that, in early 2012, researchers want to know whether the proportion of
properties in negative equity has changed. They analyse 2000 randomly selected properties
with mortgages. They discover that 552 of them are in negative equity. Use a hypothesis test
at the 5% level of significance to decide whether there is sufficient evidence to conclude that
the situation has changed since December 2010.

Be sure to state the null hypothesis clearly, and to state the conclusion clearly


Margin of error is extremely important here so to get it you take 1 over the sqaure root of the number surveyed of both you then get the amount that were actually in negative equity in both 2010 and in 2012. You then multiply this answer by the amount surveyed and add and take away the margin of error of both. I had to reject the hypothesis because the values were not corresponding ...:cool:

Nazata

Anyone get beta is less than ~33-34 degrees (I think it was around there) for the conditions under which a small error for beta will change the point R more than a small error in alpha?

Hermione Granger

Is anyone here planning to study a pure maths course at university? I Have an abysmal Guidance Counsellor and I am at a loss of what to do with myself next year. Could anyone recommend a course for me? I am studying Maths, Chemistry, Biology English Irish at higher level and that is the order of my preferance. Thanks in advance

Hermione Granger

Nazata wrote: »

Anyone get beta is less than ~33-34 degrees (I think it was around there) for the conditions under which a small error for beta will change the point R more than a small error in alpha?

How did you do that I just explained what I thought in pure English

Nazata

Hermione Granger wrote: »

How did you do that I just explained what I thought in pure English

I worked out when the point R is closer to the pivot point of alpha than to the pivot point of beta and then just found the angle beta (and added a sentence after stating the findings)

TheBody

Hermione Granger wrote: »

Is anyone here planning to study a pure maths course at university? I Have an abysmal Guidance Counsellor and I am at a loss of what to do with myself next year. Could anyone recommend a course for me? I am studying Maths, Chemistry, Biology English Irish at higher level and that is the order of my preferance. Thanks in advance

You could do a general science degree and choose 4 from say maths, chemistry, biology, physics, computer science etc. As you progress from year to year, you drop a subject. If you feel pure maths is the thing for you, you can just keep that on.

I did maths, mathematical physics, experimental physics and computer science in my first year of college but did pure maths and mathematical physics for my degree. (In N.U.I. Maynooth) Loved every minute of it. Did a postgrad in pure maths after that too.

Hermione Granger

TheBody wrote: »

You could do a general science degree and choose 4 from say maths, chemistry, biology, physics, computer science etc. As you progress from year to year, you drop a subject. If you feel pure maths is the thing for you, you can just keep that on.

I did maths, mathematical physics, experimental physics and computer science in my first year of college but did pure maths and mathematical physics for my degree. (In N.U.I. Maynooth) Loved every minute of it. Did a postgrad in pure maths after that too.

Thanks this was really helpful. I love the Maynooth campus it seems really student friendly. Do you mind me asking what kind of jobs are in this. I am 100% certain that I dont want to do research

Hermione Granger

Nazata wrote: »

I worked out when the point R is closer to the pivot point of alpha than to the pivot point of beta and then just found the angle beta (and added a sentence after stating the findings)

How did you figure this out if the angle b changes all the time

Did you do applied maths / physics and if so do you feel it helped you ?

Nazata

Hermione Granger wrote: »

How did you figure this out if the angle b changes all the time

Did you do applied maths / physics and if so do you feel it helped you ?

It will apply at a certain range of b, above this it won't so I just had to find where this range was.
I do applied maths, was very helpful for that question, particularly with the part of it...

TheBody

Hermione Granger wrote: »

Thanks this was really helpful. I love the Maynooth campus it seems really student friendly. Do you mind me asking what kind of jobs are in this. I am 100% certain that I dont want to do research

God, the sky is the limit!! Tons of jobs in computers, biotech industry in Ireland is booming so plenty of jobs there. Maths/physics could lead to jobs in finance/banking programming, statistics etc.

JailB8 xoxo

Nazata wrote: »

It will apply at a certain range of b, above this it won't so I just had to find where this range was.
I do applied maths, was very helpful for that question, particularly with the part of it...

whatever you're doing is wrong. alpha is 44 and beta is 100. if you show us the question ill tell you how to do it

Nazata

JailB8 xoxo wrote: »

whatever you're doing is wrong. alpha is 44 and beta is 100. if you show us the question ill tell you how to do it

For part A, I got those answers.
We are talking about part C, where it asks you under what conditions a small error in Beta has more effect than a small error in alpha.

JailB8 xoxo

Nazata wrote: »

For part A, I got those answers.
We are talking about part C, where it asks you under what conditions a small error in Beta has more effect than a small error in alpha.

oh sorry. for that i said that alpha>beta a small change will see a larger effect in beta and when beta>alpha a small change will see a larger effect in alpha. not too sure on that though

Nazata

JailB8 xoxo wrote: »

oh sorry. for that i said that alpha>beta a small change will see a larger effect in beta and when beta>alpha a small change will see a larger effect in alpha. not too sure on that though

It's cool.
Yeah, more or less everyone I've talked to in my school said they just said a statement so I'm curious to see if anyone else got the same answer...