OFFICIAL Edexcel S3 24th May 2017 Thread

vsauce134

Hey guys this is the official thread for the edexcel s3 2017 exam.
Post any sources you may have!!!

Reply 1

vsauce134

Yo guys do you have any more papers I can do: done all solomon and all edexcel papers online?????

Reply 2

Aruran123

Is the unofficial mark scheme out yet?

Reply 3

Qwerty Lad

Original post by Aruran123

Is the unofficial mark scheme out yet?

You found it yet mate?

Reply 4

Oddly Asymmetric

Somehow less official than unofficial but here were my answers (tell me if you got different)
a) Avantage of stratified sample over simple random:
Represents the different sub-groups' opinions on the calendar, such as different opinions of different jobs within the company
b)4,6,10,20 respectively
c) Method of stratified- List, use random numbers to draw 6 from the sample
2. a) 12.5,25,37.5
b) Test statistic was 10.667. Critical value 9.488, so reject
3. a) spearman rank was 0.7714
b) critical value was 0.8286 so insufficient evidence to reject
c) Judge trainer was ineffective
4. a) 24 30.72
26 31.28
b) test statistic 1.1763, critical value 4.605, insufficient evidence to reject
c) test statistic 7.84, so minimum significance to reject was 1%
5.a) mean=4, s^2=121.8571
b) i) [-1.061, 9.061]
ii)Assume that the times are independent
c) Not justified as in confidence interval
6. a) z=1.857>1.6449 so reject
b) Allows you to approximate the means of sample as normally distributed
7. a) (from tables) 0.0069
b) 0.9177
c)528.32

Reply 5

AM66

Original post by Oddly Asymmetric

4c wasnt it 2.5%?

and for 5b I think you had to give the actual bus times so 0830 and 0840

Reply 6

Oddly Asymmetric

You are correct about 2.5%, I guess I thought not reject. If I worked out the test statistic and v=2, how many marks will I lose because of that. Also if it was the actual times, and not the number of minutes (which it probably was, as it doesn't make sense to have a negative number of minutes) How many marks do you think I'll lose for that.
Also what are people's opinions on grade boundaries. I reckon standard 62=A, 67=A*, 73 for 100. Do people think differently?

Reply 7

AM66

Original post by Oddly Asymmetric

Probs only a few accuracy marks as u got the working right - from your answers you may have given a few to too many decimal places. Yeah I reckon standard boundaries but 75 for 100 UMS

Reply 8

Oddly Asymmetric

I thought you don't mark you down for further accuracy, and have awrt. Also they rarely give 100 for only 75 apart from in FP3, it's usually at most 74 no?- Especially since lots of people found that last combination of normal variables very difficult

Reply 9

dugdg

Original post by Oddly Asymmetric

How many marks do you reckon one lost if they 1. Used their own 's' value instead of the given standard deviation of 10, for calculating the CI? (I realised this was wrong at the end, and only managed to find the CI, writing the correct and on the next page. so not sure if i'll get the mark :frown:

) - Do you think the assumption about the observations being independent will be worth 1 mark?

I also got a result for d^2 in the spearman question :frown:

- and i split the 5% sig level in the normal battery question into 2.5% for some stupid reason. Any ideas on how many marks i'd lose there? (As a result i accept ho, instead of rejecting it).

(edited 6 years ago)

Reply 10

Pelop

Original post by Oddly Asymmetric

Sorry but what do you mean by saying they give 100 if above 75 . Meaning if you get 75 % and more they will give you an A* ?

Reply 11

sebastian1892

guys at the question with the spinner i wrote in my Ho and H1 that discrete uniform distribution is a suitable model and is not a suitable model respectively rather than continuous uniform. will i lose both marks? will i lose the mark for my conclusion as well or follow through will apply there?