S1 May 2012 - Post Exam Thread - Paper and Solutions in the FIRST POST

Did you make your method 100% clear eg. by drawing a tree diagram? If so then you definitely won't lose all the marks.

Okay there's 1 thing i don't understand.. the question that asks you to find the minimum thinning of the shell that results in death, given that pollutant levels above 16 are likely result in the death, how come you have to use 16 and not 17 in your regression line? Cause i thought about it during the exam, and it said pollutant levels above 16 result in death, so wouldn't you have to use 17?

Yeah I drew a tree diagram, the same as the one before but with fading added onto the end, just with 0.5 instead of 0.05. Do you reckon I could get half marks for each question? (I.E 3/6 for both parts together).

think i achieved 60/75
I hate s1...
Resitting this next year

Okay there's 1 thing i don't understand.. the question that asks you to find the minimum thinning of the shell that results in death, given that pollutant levels above 16 are likely result in the death, how come you have to use 16 and not 17 as the value of p in your regression line? Since pollutant levels above 16 result in death, wouldn't you have to use 17?

Yeah, you could probably get around half the marks. I definitely won't get anything for writing that P(B) and P(T) are independent and 'proving' that though...

Yeah, you could probably get around half the marks. I definitely won't get anything for writing that P(B) and P(T) are independent and 'proving' that though...

S1 May 2012

Not sure what to make of this paper, certainly required a little more thought than normal

Q1 - DRV

Easy


Q2 - PMCC

Easy


Q3 - Linear regression

Bit weird but pretty easy


Q4 - Venn

So stupidly easy


Q5 - Measures of location / spread

Very weird - you could have quite easily solved it by spotting that there were 22.5 5x5 squares so each 5x5 square represented 20 cars.

However I think this will be a massive bloodbath with many students picking up no marks.


Q6 - Normal distribution

Harder than normal I would say; I used the % points table to answer b) and c)


Q7 - Probability

Fairly easy but pretty unusual


I am going for

75 - 100ums
68 - 90ums
61 - 80ums
53 - 70ums
45 - 60ums
37 - 50ums
29 - 40ums



This thread will be locked at somepoint and then unlocked at midnight following the Stats 1 examination.

I will upload the paper and my solutions to this post.

I will do my best to answer questions about the paper but please try to read the thread first so that I am not answering the same questions lots of times.

Here are some links to previous S1 threads, they are worth a read and you will see what the common errors were...

S1 Jan 2012 - http://www.thestudentroom.co.uk/showthread.php?t=1865940

S1 June 2011 - http://www.thestudentroom.co.uk/showthread.php?t=1619124

The second link contains loads of past papers, model answers etc

Good luck.

Okay there's 1 thing i don't understand.. the question that asks you to find the minimum thinning of the shell that results in death, given that pollutant levels above 16 are likely result in the death, how come you have to use 16 and not 17 in your regression line? Cause i thought about it during the exam, and it said pollutant levels above 16 result in death, so wouldn't you have to use 17?
I'm wondering the same thing

I'm wondering the same thing

hey, could someone explain why the value used in the regression line in 3f is 16 and not 17? I'm not denying that it's right, I'm just confused as the question said pollution levels above 16 are likely to result in death so to find the minimum thinning of a shell, why would we use 16 if it's levels above 16 that are likely?

p is a continuous variable so 'above' 16 is equivalent to 16 and higher.

Oh no! How did you manage that?

Thanks a bunch for the mark scheme!!!!

only a few questions:
For 3B) does you think they'll accept - there is strong positive correlation
For 5A) i got the same answer but working was very different (sort of)
E.g. i work out area under graph in terms of x to get 112.5x, then divided the total 450 by this to get 4 for each square, then area of those above 35, would i still get full marks?
For 6c) i might have used women's SD when you had to use men's SD, how many marks would i lose?


Thanks, much appreciated

Definitely 16. You could argue that at 16.0000001, and so on is the point at which it is above 16 and therefore will cause the death at that moment, so as it is so close to 16, you would simply just take it as 16. They may give you the marks for 17 though, who knows.

wait if i subbed in the wrong value for the pmcc will i still get a mark for method?

Hey two questions, if anyone can answer i'd appreciate it a lot:

1. For question 4a i gave two examples which were (B n W) and (T n W) . Each one is correct but would i be marked down for giving two? i got the explanation correct btw...

2. For question 5e would i get away by saying that the data is almost symmetrical and therefore it would be appropriate to use the mean? Also for question 5d i said the distribution was symmetrical for the same reasons above, again would i get the marks?

Thank you