**HL Maths P2 Before/After

ferike1

http://www.independent.ie/national-news/leaving-cert-new-style-maths-papers-tough-but-mostly-manageable-3136231.html

According to the teachers it was easy :rolleyes:

Cosmic.Postman

Not too bad, but seriously poor form SEC. I was under the impression going in to the exam that the null hypothesis had been deferred!!

How much would I get for doing out the confidence interval and saying that .31 wasn't inside it so there was a change since December 2010?

Mista

Cosmic.Postman wrote: »

Not too bad, but seriously poor form SEC. I was under the impression going in to the exam that the null hypothesis had been deferred!!

How much would I get for doing out the confidence interval and saying that .31 wasn't inside it so there was a change since December 2010?

I think 5% significance level and 95% confidence interval are the same?

Chuchoter

Cosmic.Postman wrote: »

Not too bad, but seriously poor form SEC. I was under the impression going in to the exam that the null hypothesis had been deferred!!

How much would I get for doing out the confidence interval and saying that .31 wasn't inside it so there was a change since December 2010?

That was my answer too

Theorems

ferike1 wrote: »

http://www.independent.ie/national-news/leaving-cert-new-style-maths-papers-tough-but-mostly-manageable-3136231.html

According to the teachers it was easy :rolleyes:

Nooooooo :'( if they mark it hard cause it's 'easy' it's hello to 6th year once more for me

emmamurphy233

DepoProvera wrote: »

emmamurphy233 wrote: »

K was four. I'm almost 100% sure.

How'd you do it?? I'm dying to know

Got the radius and centre of the circle by doing simultaneous equations with the information given, then used the perpendicular distance formula to get k. It ended up as a quadratic and k was one or four. The fact that the question specified it wasn't one makes me very confident that my method was correct.

DepoProvera

Cosmic.Postman wrote: »

Not too bad, but seriously poor form SEC. I was under the impression going in to the exam that the null hypothesis had been deferred!!

How much would I get for doing out the confidence interval and saying that .31 wasn't inside it so there was a change since December 2010?

That's correct. But it said state the null hypothesis which was just that it =.31 and conclude which means you cannot accept the null hypothesis so there is evidence that there was a change.

Cosmic.Postman

Mista wrote: »

I think 5% significance level and 95% confidence interval are the same?

Yeah, I know that. I only found out after the exam that when it says state the null hypothesis clearly in the exam, you just have to say "we reject the null hypothesis". Or something like that.

RedTexan

Damogib wrote: »

Did anybody work out k in question 3 ? I tried a load of methods but just couldn't work it out. Also i got 124 in part (i) on question 5 and a 84% increase

Sure it wasn't a 94% increase?

DepoProvera

emmamurphy233 wrote: »

Got the radius and centre of the circle by doing simultaneous equations with the information given, then used the perpendicular distance formula to get k. It ended up as a quadratic and k was one or four. The fact that the question specified it wasn't one makes me very confident that my method was correct.

Well done for getting it, it was tough..! I got g^2=f^2=c and that was a far as I went down that root I think..

Mista

DepoProvera wrote: »

That's correct. But it said state the null hypothesis which was just that it =.31 and conclude which means you cannot accept the null hypothesis so there is evidence that there was a change.

I just said that the null hypothesis was that there was a change? And then accepted it.

Hayezer

If I had got the battery question and some of question 8 I would have been pleased overall. Knew I wasn't going to get Q3 and say I got most marks for all the other short questions and good few for Q7. Q8 was abysmal, say I got about 10 marks out of 75.

ferike1

My brother said the exam was easy. All about understanding maths and not just learning it off.

DepoProvera

Mista wrote: »

I just said that the null hypothesis was that there was a change? And then accepted it.

I'd say that's right aswell. The lads in the thread yesterday said you can choose what the null hypothesis is

Cosmic.Postman

DepoProvera wrote: »

That's correct. But it said state the null hypothesis which was just that it =.31 and conclude which means you cannot accept the null hypothesis so there is evidence that there was a change.

Hardly fair that there's no mention of the null hypothesis in my book. Oh well! I'm hoping not too many marks were going for stating the null hypothesis.

MattHelders

For the hypothesis. Was 0.31 the null hypothesis?

I then got the margin of error and both numbers were lower than 0.31 so I said it has changed. I don't think I did it right. Kind of just guessed in the exam.

RedTexan

DepoProvera wrote: »

I got 124 or 134 for the first part which a few people agreed with, but then again a few got 32 so who knows :rolleyes:

i got 124 as well, my z scores in the first one were -2.5 and 2.5 and then in the second one my z scores were -3 and 2

reznov

ferike1 wrote: »

My brother said the exam was easy. All about understanding maths and not just learning it off.

Yeah considering the fact that there was more writing than mathematics. How can you learn Maths off? Lmao. As the independent wrote - "common sense and general knowledge". Doesn't equate to Maths.

c28omzk7ihsxv0

I thought null hypothesis wasn't for our year
I just did the 1/root n formula and thats all. Will I get any marks?

Chuchoter

The null hypothesis is that it hasn't changed. The alternative hypothesis is that it has.

RedTexan

Chuchoter wrote: »

I got k=2/3 or 0 then I rejected 0 as it doesn't cross the origin.

I got k=1 and k=5.282 or something which seemed right because if k was equal to one it was the first tangent and as k was said to be greater than 1 the other value would fit? There is a lot of grey area still surrounding that paper

Mista

RedTexan wrote: »

i got 124 as well, my z scores in the first one were -2.5 and 2.5 and then in the second one my z scores were -3 and 2

I got 124 as well... did anyone use the emperical rule for the 2nd part? Like, half of 95 and half of 99.7, then add them?

Cosmic.Postman

RedTexan wrote: »

i got 124 as well, my z scores in the first one were -2.5 and 2.5 and then in the second one my z scores were -3 and 2

That's what I got too. I then got the percentage increase in rejected ones as like 1.2% (or something like that). It seems looking at everyone else's answers, that I was way off.

DepoProvera

RedTexan wrote: »

i got 124 as well, my z scores in the first one were -2.5 and 2.5 and then in the second one my z scores were -3 and 2

The z scores should have been the same for both on the second one, no? Because the mean was increased to 20.05 and the range was still .25?

Mista

DepoProvera wrote: »

The z scores should have been the same for both on the second one, no? Because the mean was increased to 20.05 and the range was still .25?

I dont think so, because they were still only accepting batteries in the same range? Within 0.1mm of 20?

Cosmic.Postman

DepoProvera wrote: »

The z scores should have been the same for both on the second one, no? Because the mean was increased to 20.05 and the range was still .25?

The mean was increased, but then that would've meant you could only have ones plus .2 or minus .3 of the mean?

RedTexan

DepoProvera wrote: »

Well done for getting it, it was tough..! I got g^2=f^2=c and that was a far as I went down that root I think..

did the exact same thing, ended up with k=1 and something else, not four though, might have made a small error. Should get a high majority of the marks with this new fangled scheme. what did you get for the centre of the circle (if you can remember) I came out with (2+root2, 2+root2)

DepoProvera

Mista wrote: »

I dont think so, because they were still only accepting batteries in the same range? Within 0.1mm of 20?

0.1 was the standard dev... But if you mean it was .25 of 20 then damnnit I must have confused that in the exam

Hayezer

Mista wrote: »

I got 124 as well... did anyone use the emperical rule for the 2nd part? Like, half of 95 and half of 99.7, then add them?

I tried emperical rule for all that question stupidly. Mean was 20, SD 0.10 and limit was 19.75-20.25. So I thought it was 2.5 standard deviations from the mean which is 97.35. So I thought that leaves 2.35% of faulty batteries, so I multiplied 0.0235 by 10,000 and got 235 (wrong :L). If any of that makes sense :L.

Hopefully a few attempt marks

mathstalk

Need to know: Did anybody else get 2+root(2) for k?
Also, did anybody else's graph end up as a half doughnut?