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# Arsey's S1 Edexcel Summer 2013 Model Solutions BOTH PAPERS watch

1. (Original post by Graham981)
Likely an A, but depends on how high the A's were in C1 & C2 eg :

If you got : 84 in C1 (A)
84 in C2 (A)
71 in S1 (B)

it will be 239/300 which is a B

but say you get eg : 86 in C1 (A)
87 in C2 (A)
71 in S1 (B)

= 244/300
= A

My predictions are:-

64/75 - C1
55/75 - S1
-Guessed C2--
65/75 - C2
2. I assumed that the event of a worker taking the bus to work and the event of a worker being part time etc. to be independent, if I got the Venn diagram shape right but the probabilities wrong, do I get any method marks for adding up the intersection or do I get 0/6?
Also, for the box plot, I got a negative number for the lower limit for some reason so obviously I didn't plot the outlier or the 'lowest datum before an outlier'' correctly. How many marks would you reckon I'd lose?
Finally, what would 66/75 be in UMS roughly?
3. For question four it can't be positive skewness because:

Q2 - Q1 > Q3 - Q2

But 3(mean - median) / SD gives a positive skewness??

helpp pleaassseeee ;')
4. (Original post by Azuria)
Yaaaay! I think I did everything correct apart from the silly written questions xD I found this paper really easy... I finished it with 40 minutes to spare D: I think those who did the venn diagram with one single circle in the middle with different sections split in 3 will also get the mark, since it was in a past paper before. ...Did anyone instantly think of the pokemon jumpluff when they did the exam? XD (for the venn diagram)
Hey, do you know which past paper this was in? Just that I want to check that what I'd drawn is ok!

Thanks
5. (Original post by momo26396)
For question four it can't be positive skewness because:

Q2 - Q1 > Q3 - Q2

But 3(mean - median) / SD gives a positive skewness??

helpp pleaassseeee ;')
Yeah, I found this when I did it, but the question "why should the mean/s.d not be used?" was only one mark so all you had to say was that it was skewed I think. It didn't matter which way it was skewed.
6. (Original post by Olly2304)
Yeah, I found this when I did it, but the question "why should the mean/s.d not be used?" was only one mark so all you had to say was that it was skewed I think. It didn't matter which way it was skewed.
Median and IQR are used when distribution is skewed and there are outliers. So using mean and SD was inappropriate since they are affected by outliers and the data was skewed.
7. Loved no.5 got it all right!

for got zero's in venn for middle but I put 0 outside the circle in the box, also I didn't do 3sf on no.1 (so I only added 1 mark).
I misread the box plot so got the wrong mode

for 4.e I put the stnd dev and mean is suitable when data is symmetrical this data has a negative skew (do I lose the mark because I got the skewness wrong

same with the last question, I used the percentage point table and did 0.1 instead of 0.01 do I still get method marks for : the graph, 2 writing the equation, and then lose the other 2?

if so I got 60 woooop!
8. ARGHH I PUT 7.5 IN MY CALCULATOR INSTEAD OF 7.8 FOR 6B, GIVING ME THE WRONG PERCENTAGE. I'M A RIGHT IDIOT
9. On 4e) I simply put 'Data is skewed'. Would I get the mark?
10. Hi guys it would be really appreciated if you tell me how many marks I'd lose for a) giving .0274 I think it was instead of a percentage (the normal distribution q)
b) for the Venn diagram I drew little circles inside all three events, I got all the numbers right just the drawing completely wrong

Cheers
11. For the very very last normal distribution, is it possible for a range of answers depending on what you used off the table? I got 2.07? So fairly close :s

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12. (Original post by momo26396)
For question four it can't be positive skewness because:

Q2 - Q1 > Q3 - Q2

But 3(mean - median) / SD gives a positive skewness??

helpp pleaassseeee ;')
It's weird that, but I think they tell you if you are meant to use that because it might apply to a certain range of values? :s

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13. (Original post by own)
It's weird that, but I think they tell you if you are meant to use that because it might apply to a certain range of values? :s

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I put Mean is affected by extreme values. Any mark?
14. (Original post by Freddy-Francis)
I put Mean cannot be affected by extreme values. Any mark?
I said something similar, I said it is skewed with some extreme values
15. (Original post by Freddy-Francis)
I put Mean is affected by extreme values. Any mark?
The mean does get affected by extreme values..
16. (Original post by Robbie242)
I said something similar, I said it is skewed with some extreme values
I meant mean is affected by extreme values :P
17. (Original post by Freddy-Francis)
I put Mean cannot be affected by extreme values. Any mark?
If data is skewed you use median and inter quartile because it ignores extreme values, but if it is not skewed then you use mean and standard deviation (think about the shape of a normàl distribution) so I'm not sure, maybe not. :/

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18. (Original post by mynameisntbobk)
The mean does get affected by extreme values..
yeah thats what i put
19. I found this paper harder than C1 just a few silly errors, I think I got 59/75 for S1 and 71/75 for C1 just hope that C2 is nice
20. Anywayz what do u guys have next. I have Physics retake on Monday.

Good Luck to All!

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Updated: December 2, 2013
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