MAY11 Math HL paper 3

[jezze]

So how were the options?

Sets, relations and groups was ridiculously easy compared to some other years - no difficult proofs, even a question on set difference. Hope the grade boundaries are not too high...

[slack]

I did Series and Differential Equations... I hope I'm not the only one, but it was a lot harder this year!!!

[lexie]

Stats and Probability TZ2 was way harder than anything before

[ocfx]

Well I don't know if it was the ridiculous amount of studying that I put in for paper 3 (stat and prob TZ2) or just that the paper was pretty straight forward, because I essentially managed to answer everything excluding the last question, which I didn't think about properly because I was intimidated by the idea of simplifying combinations and logarithms at the same time (probably not that hard). But I think P3 definitely raises my math overall grade possibly even to a 5 (in conjunction with my IA), but I'm pretty sure I've got at least a four.

Just happy it's over We find out in July then...

Edited May 10, 2011 by ocfx

[chrypton]

So how were the options?

Sets, relations and groups was ridiculously easy compared to some other years - no difficult proofs, even a question on set difference. Hope the grade boundaries are not too high...

I agree completely! It must have been amongst the easiest paper 3s. I managed to finish everything so really hoping this paper can make up for paper 1 and 2(not that I did horrendous on those)

[Slovakov]

I did sets, relations and groups, and I've got the same feelings. I wasted too much time for the first task, but I haven't seen such an easy paper since... 2006 I think

[Jonathan Dawson]

I had differential equations and series. The first three questions were easy. the fourth one was hard. and the last one was horrendous.

[JayC]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

[suggaplum]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

Really? I thought questions 1, 2 and 3 were quite generic... Question 5 was actually maths like though, which is not really seen in past papers with all the ln stuff and the algebraic manipulation

[iB dweeb]

Loved Paper 3 Sets Relations and Group Theory. It was amazing! Mwah!

[n0urhan]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

Really? I thought questions 1, 2 and 3 were quite generic... Question 5 was actually maths like though, which is not really seen in past papers with all the ln stuff and the algebraic manipulation

It wasn't a difficult paper but yes i though the last question was very strange! It had nothing to do with probability, you just copy the equation and the rest was calculus!!

I panicked and I left part of the question unanswered :'(

The rest was good though

[suggaplum]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

Really? I thought questions 1, 2 and 3 were quite generic... Question 5 was actually maths like though, which is not really seen in past papers with all the ln stuff and the algebraic manipulation

It wasn't a difficult paper but yes i though the last question was very strange! It had nothing to do with probability, you just copy the equation and the rest was calculus!!

I panicked and I left part of the question unanswered :'(

The rest was good though

I could not do question 4 cus I completely forgot that the mean and variance is the same in a Poisson distribution. I thought the last question was quite okay though, as long as you are good with algebraic manipulation. At first it kinna scared me, but it wasn't that bad. A lotta people didn't get to do the last part of the last question.. including me I just hope I can get a 7 overall, despite my absolutely horrible paper 1...

[n0urhan]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

Really? I thought questions 1, 2 and 3 were quite generic... Question 5 was actually maths like though, which is not really seen in past papers with all the ln stuff and the algebraic manipulation

It wasn't a difficult paper but yes i though the last question was very strange! It had nothing to do with probability, you just copy the equation and the rest was calculus!!

I panicked and I left part of the question unanswered :'(

The rest was good though

I could not do question 4 cus I completely forgot that the mean and variance is the same in a Poisson distribution. I thought the last question was quite okay though, as long as you are good with algebraic manipulation. At first it kinna scared me, but it wasn't that bad. A lotta people didn't get to do the last part of the last question.. including me I just hope I can get a 7 overall, despite my absolutely horrible paper 1...

I did quite terrible on paper 1 too! Many people I know didn't think it was so difficult so I though I was screwed but I really think it was a very TOUGH paper & hopefully the boundaries will be low!I did waay better in paper 2 and okay in paper 3 so I'm hoping for the 7 too!

U really can never know with math HL, the boudaries can change quite drastically so there is always hope

[Nishad Potdar]

TBH, Stats was an unconventional paper... Questions like question 5 and finding the confidence level of t-distributions haven't really been asked before. But I did quite well. Hoping that this paper goes a long way in making up my lost paper 2.

[Snoopchicken]

Stats was definitely different than past years. While I did good (+50), I know most of my friends didn't. I think the main questions people had trouble with were the last part of question 3 (where they asked for T Confidence Level), question 4 (although it was straight forward), and question 5 (barely related to the chapter lol).

[AvifromtheOC]

I did series and Diff. Equations and it was a pretty tough paper this time, in parts at least.

THe 1st 3 questions were fairly straightforward and easy but the last 2 questions were very difficult. Let's hope the boundaries are low for paper 3.

[Nishad Potdar]

@Snoopchicken- What confidence level did you get for the t-distribution question. For Q.4 part 1, the CL was 99% and the SL was 1%, right? For the t-distribution, I got something like 96.5%

[JayC]

Stat and Prob was okay. Not hard but weird. The questions are not the type I usually see in past paper. But once I got what they were asking for, it's kinda straight forward.

Really? I thought questions 1, 2 and 3 were quite generic... Question 5 was actually maths like though, which is not really seen in past papers with all the ln stuff and the algebraic manipulation

It wasn't a difficult paper but yes i though the last question was very strange! It had nothing to do with probability, you just copy the equation and the rest was calculus!!

I panicked and I left part of the question unanswered :'(

The rest was good though

I could not do question 4 cus I completely forgot that the mean and variance is the same in a Poisson distribution. I thought the last question was quite okay though, as long as you are good with algebraic manipulation. At first it kinna scared me, but it wasn't that bad. A lotta people didn't get to do the last part of the last question.. including me I just hope I can get a 7 overall, despite my absolutely horrible paper 1...

I did quite terrible on paper 1 too! Many people I know didn't think it was so difficult so I though I was screwed but I really think it was a very TOUGH paper & hopefully the boundaries will be low!I did waay better in paper 2 and okay in paper 3 so I'm hoping for the 7 too!

U really can never know with math HL, the boudaries can change quite drastically so there is always hope

Question 5 was like more of a paper 2 question I thought. I had to find intersection of two functions in order to get the answer, which is REALLY weird.

[Snoopchicken]

@Nishad, yeah, I got 96.6% And in the beginning of question 4 (part a), they tell you to use the significant level of 1%. But that's a whole other story - that's a one tailed test.

Part b was pretty easy, just not conventional. First, you find the difference between the 2 values they give in the confidence interval. This is equal to 2tSn-1/rad(n), and you have everything except "t", so obviously you find "t" from this. After you get that value of "t", you should recognize that the CI is 2 tailed and do "tcdf" on the calculator from "-t" to "+t", and degrees of freedom 9. It ends up being like 0.965... and I remember I rounded the 3rd significant digit up.

It's right BTW, I was able to check using GDC (I performed T-Interval)

BTW, JayC, for part B in question 5, the answer is 6, correct? You try to find the value of Y which gives the highest probability in the NB distribution, and thus, you look for the integer value of Y which yields the value closest to 0 in f'(x)/f(x) (function is at max when derivative=0).

[Nishad Potdar]

@Nishad, yeah, I got 96.6% And in the beginning of question 4 (part a), they tell you to use the significant level of 1%. But that's a whole other story - that's a one tailed test.

Part b was pretty easy, just not conventional. First, you find the difference between the 2 values they give in the confidence interval. This is equal to 2tSn-1/rad(n), and you have everything except "t", so obviously you find "t" from this. After you get that value of "t", you should recognize that the CI is 2 tailed and do "tcdf" on the calculator from "-t" to "+t", and degrees of freedom 9. It ends up being like 0.965... and I remember I rounded the 3rd significant digit up.

It's right BTW, I was able to check using GDC (I performed T-Interval)

BTW, JayC, for part B in question 5, the answer is 6, correct? You try to find the value of Y which gives the highest probability in the NB distribution, and thus, you look for the integer value of Y which yields the value closest to 0 in f'(x)/f(x) (function is at max when derivative=0).

Are you sure that it was 96.5%? Wow! I am so relieved!!! I did this Q. in a slightly diff style though. Can you confirm that the value of t was something like 2.42? I got 96.5% using this t-value and 9 degrees of freedom. And I can confirm that for part B in Q.6 "6" was the correct answer! I did this question using two methods in the exam hall. One by setting the derivative=0. And then I got bored, so I used the tables in my GDC and got the same answer again (max probability at Y=6).

I am still doubtful about Q.4 (The one whose part b was on Type II errors). They had given 2 critical regions, so it obviously was a two tailed test, no? And they had asked to find the SL for this interval. I got the CL as 99% and SL thus as 1%. Used mean=variance for Poisson Dist...