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Edexcel s1 June 2016 unofficial mark scheme

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[QUOTE=KevinClyde;65800621]You were told they were independent so P(AnB)= P(A) x P(B) then rearrange. I almost forgot to add the value at the bottom of the circle, maybe you did that?
Holy crap 😊
Grade boundary predictions anyone? :smile:

I think I got 63-65/75, just hoping it's a mid-high A :/
Original post by tripleseven
Grade boundary predictions anyone? :smile:

I think I got 63-65/75, just hoping it's a mid-high A :/


I'd say pretty standard, if anything slightly lower boundaries.
Original post by veldt127
Well, E(x) is the sum of x over n, right?

E(1/x) is the sum of 1/x over n.

(p(X = x)( (Σ1/x) )/n is not the same as (p(X = x)(1/( (Σx)/n ))
To maybe simplify this explanation with an example, the gist of the reason is that Σ(1/x) is not equal to 1/(Σx).

For instance, take two values: x = 2 and x = 3.
1/(Σx) = 1/(2+3) = 1/5
Σ(1/x) = 1/2 + 1/3 = 5/6
So the two are completely different.
Can someone pls post model answers with how many marks each question was?
Original post by ShatnersBassoon
To maybe simplify this explanation with an example, the gist of the reason is that Σ(1/x) is not equal to 1/(Σx).

For instance, take two values: x = 2 and x = 3.
1/(Σx) = 1/(2+3) = 1/5
Σ(1/x) = 1/2 + 1/3 = 5/6
So the two are completely different.


Thanks, I was struggling to get that across without huge amounts of brackets :smile:
Original post by Jackhawkins21
3c> was -131.9 and 5 Cii> was 0.689


I got this too
Original post by ShatnersBassoon
The question was 3 marks. In the worst case, no, you'd get 0/3 (1 mark for saying it's a bad model; another for saying mean =/= median; a third for comparing d to the actual answer).

You didn't compare your answer to part (d) to anything, but the question explicitly told you to, so you've definitely lost a mark there. I'd give you 1/3 but maybe if they're generous you'd get 2/3.


Thanks
Looks like some threads were merged together. Whoever is now the OP, can you make a poll with number of marks people think they got? helps with predicting. @glad-he-ate-her
70 - 75
65-70
60-65
55-60
50-55
45-50
40-45
less than 40
Reply 49
Avatar for Maetras
Maetras
9
Original post by veldt127
Ok, I managed to get all my answers stored in my calculator at the end, this is what I got. Not 100% sure on all of them, but we can compare.

Question 1

Spoiler

Question 2

Spoiler

Question 3

Spoiler

Question 4

Spoiler

Question 5

Spoiler

Question 6

Spoiler



What was 2.35 for?
Mate there was a VERY similar question in one of the past papers, fortunately did it the night before hahah - You just had to subtract the value they gave from 1 to get 0.18, and "P(X<u)" is just the mean, and the mean represents 0.5 in a normal distribution model; therefore 0.18/0.5 = 0.36.
Original post by WreckTangle14
Im super super confused with question 6c, i had NO idea it completely threw me off, could anyone explain?


Mate there was a VERY similar question in one of the past papers, fortunately did it the night before hahah - You just had to subtract the value they gave from 1 to get 0.18, and "P(X<u)" is just the mean, and the mean represents 0.5 in a normal distribution model; therefore 0.18/0.5 = 0.36.
Original post by veldt127
Ok, I managed to get all my answers stored in my calculator at the end, this is what I got. Not 100% sure on all of them, but we can compare.

Question 1

Spoiler

Question 2

Spoiler

Question 3

Spoiler

Question 4

Spoiler

Question 5

Spoiler

Question 6

Spoiler



please can you tell me how you worked out Q2 f i and ii ? like the general ideas of going about it ? thank you :smile:
Original post by logicmaryam
I'm pretty sure I got it wrong haha but ill add your answer and others' so people can discuss it.


This is the definition of standard deviation : a quantity expressing by how much the members of a group differ from the mean value for the group.

Therefore if there is another value in the data and it is the same as the mean, overall the data should be less weighted away from the mean.

I might be wrong but..
Original post by tripleseven
Grade boundary predictions anyone? :smile:

I think I got 63-65/75, just hoping it's a mid-high A :/


Considering how easy the paper was...

72 - A
70 - B
12 - C
8 - D

etc etc, you get the pattern
Original post by azizadil1998
This is the definition of standard deviation : a quantity expressing by how much the members of a group differ from the mean value for the group.

Therefore if there is another value in the data and it is the same as the mean, overall the data should be less weighted away from the mean.

I might be wrong but..


odds are
Original post by glad-he-ate-her
1.0.994
w=0.721 + 0.0142d
5.691 response was wiggle
2.p=0.175 q=0.15
varx=2.115
E (r) was 0.45 rebecca and sarah winning 0.475 0.375
3. 2.35 -133.9 -0.754
4.0 0.03 0.22 0.45 0.405 33 was number of diners
5. K=0.5
h=17
med=3.47
0.68
0.2546
6. 0.0668
206.336
0.36

Feel free to correct or give answers to non numerical questions


Can OP do a public google drive doc where everyone can contribute by adding marks, answers and questions? @glad-he-ate-her
Original post by bobbutitii
odds are


unfortunately the odds are always against me
Original post by azizadil1998
unfortunately the odds are always against me


cool story bro, you'll get used to it.
Original post by bobbutitii
cool story bro, you'll get used to it.


NEVER, what did you write

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