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Arsey's S1 Edexcel Answers 18th Jan 2013

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Hey, I was just wondering in the exam yesterday while answering the questions I underlined my answers to the questions and they were in order I just didn't put the part a b c down will the markers be leanient and mark them or will they be strict and say because I haven't labelled it they will mark a correct answer wrong ?

Reply 81

EL77

Original post by Mister Cery

Can't believe I didn't realise 4c) was a given that question :frown:

neither did i, do you think we'll get marks for not doing at as a given question?

Reply 82

Arsey

Original post by chignesh10

Is he last part 5e) and f) wrong . I got 0.4038 for e) but I am not sure?

What is the answer to part 5e).

Also for the tree diagram question, I misread teh question completely and worked out the probability of winning when you choose either die...so I got 1/3 for the blue die and 1/4 for the red die... I will lose all 4 marks won't I

0.4038 from normal distribution is correct. Well done, I think that is pretty hard

Reply 83

Arsey

Original post by EL77

guys you see the value for the skewnwss question the value was like 0.75 which is such weak skewness that the mean practically equals the median which would support normal distribution? thats what i thought, as well as using the probability value i wrote that

0.75 isn't weak skew

for normal distribution to be suitable one criteria is that mean must be equal to the median (or very close to).

Reply 84

JASONDILL

how much would you get on 4c) for doing P(127<L<133)

and avisha winning i got 7/12 but the correct answers of which to choose for each situation

Reply 85

chignesh10

Original post by Arsey

0.4038 from normal distribution is correct. Well done, I think that is pretty hard

and for f) i said her suggestion is invalid / wrong / unreliable as normal distritbution can only be used when there is symmetry about the mean, and as there is a very large positive skew, the normal distribution cannot be used. Is that right? and i said for a normal , mean = median but it isn't in this case

Reply 86

Part A

Being realistic, this was a much harder paper than Jan 12 (I did it a few hours before this exam).

I just looked at Arseys thread for S1 Jan 12 and he predicted it would be 75/75 for 100 ums and was a easy paper. Given that this was much harder, I would be inclined to say that 100 ums will be around 69-72.

P.S. for jan 12, it was only 72/75 for 100 ums so Arseys predictions aren't always correct. Props to him for uploading though, I'm just laying out the facts..

Reply 87

YathTheMagician

yes guys in q5e i got 0.4038 by doin 0.2981+0.2981=0.5962 then 1-0.5962=0.4038 but arsey show it is something els can someone help me out

Reply 88

KhanR

what do you think the grade boundaries will be 61/75 for an A?

Reply 89

Zytex

Original post by JASONDILL

how much would you get on 4c) for doing P(127<L<133)

and avisha winning i got 7/12 but the correct answers of which to choose for each situation

If you method marks are all correct maybe 3, but I think it is more likely you will get 2. I did the same :frown:

Reply 90

trentjoseph007

one of my friend did P(127<L<133) .. would he get any mark for it

Reply 91

ljh950912

Original post by Part A

Thats what im hoping

Posted from TSR Mobile

Reply 92

jayzel

Well, I guess I will be retaking this exam! x

Reply 93

Titus20

Anyone wanna have a stab at 100% UMS and 90% UMS?

Reply 94

ljh950912

Original post by Part A

Yeah there was nothing tricky about jan 12 but this had several tricky parts..hopefully, we'll see in march I guess!

Also i guess ppl didnt have a good exam condition because of the snow, etc. Yeah hopefully i got more than 95 ums

Posted from TSR Mobile

Reply 95

Part A

Original post by Titus20

Anyone wanna have a stab at 100% UMS and 90% UMS?

I'm predicting 70-71 for 100 ums. I'm no expert but basing it against jan 12 grade boundaries. Be interesting to hear Arseys opinion on this..

This was posted from The Student Room's iPhone/iPad App

Reply 96

Humzah96

Original post by Humzah96

I thought it said B OR NOT C :frown:

how many marks would i lose? And for regression i got my variables wrong so subbed them in wrong etc how many marks would i lose out of 5

This was posted from The Student Room's iPhone/iPad App

This was posted from The Student Room's iPhone/iPad App

Reply 97

Brutal_Pigeon

I think the paper felt OK overall, as people said there were some tough bits

Nasty kick in the teeth when I read Arsey's MS - the Normal Distribution question involving having to recharge the phone after 133 hours! I just said the probability of not having to charge at all until 133 hours, rather than the probability of not having to charge given that the phone did not require charging before then. Badly worded if you ask me!

Even so, not nearly as brain-addling as the second-last question. It seems the hardest bit of S1 is trying to work out the motive and rules of the increasingly arcane games people come up with!

Also, P([BnC]') has never come up before. I've never seen that notation, and neither had my teacher, at least in an S1 exam. Hopefully the markers will feel charitable.

(edited 11 years ago)

Reply 98

Humzah96

Arsey please respond

This was posted from The Student Room's iPhone/iPad App

Reply 99

ljh950912

Original post by Arsey

Finally managed to start a thread....

Q1. Standard correlation. I think the mark scheme will be very generous in part c)

Q2. DRV. Pretty easy if you revised cumulative distribution questions.

Q3. Regression. Fairly easy as it was obvious that t was x.

Q4. Normal distribution. Standard apart from c) I think that will cause a lot of problems.
I think part c) is very badly worded.

Q5. Measures of location/spread. Standard. The histogram part is very easy but always causes problems.

EDIT

parts e) and f) are going to lead to an absolute bloodbath

part e) you had to calculate the prob using normal distribution (for 2 marks!)

part f) you had to say it seems reasonable since Prob from table is 0.40 but it isn't suitable since data is skewed

I think most candidates will get 1/4 at most.

Q6. DRV/Probability. Quite a confusing question, I think this will cause quite a few problems.

Q7. Venn. I thought this was pretty easy but I can see it causing a lot of problems.

Not really sure about the grade boundaries. It seemed pretty standard. Maybe 61 for an A.

Given the bloodbath that will happen I am inclined to reduce it down to 60/75 for an A