Edexcel S1 - 15th June, 2016 [Exam Discussion]

Reply 1480

LukeB98

4

Original post by Messi555

This is a maximum concurrence. Thank you.

Concurrence please.

Is there an official unofficial mark scheme?

Reply 1481

iMacJack

16

Original post by iMacJack

Anyone please remember the workings out and answer for Sxy

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Reply 1482

04MR17

Volunteer Section Leader

22

I laughed so hard at the dancing/wiggling bees. The invigilator came over to ask me if I was crying.

Reply 1483

neyjunior

2

Original post by zandneger

R= 1/X

Hence E(R)=

(1/(-2) * 0.175)+(1/(-1) * 0.15)... + (1/(2) * 0.175)
Basically take 1 over the values when calculating E(X) and multiply by the probability for each. Hope this helps :wink:

Thank you very much :smile:

what answer should that give by the way?

Reply 1484

justalawyer1998

5

Original post by Princepieman

Srs? Are you going to snap a picture of your nether regions and compare it too?

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I don't understand what you're saying but yeah sure. Wiggle.

Reply 1485

Tomilolaa

1

Original post by CrazyFool229

Haha yeah I did that method too. Does seem harsh for 1 mark when I have seen questions like that worth 3 marks on the Solomon papers.

Yeah , I feel like they swapped marks around on that paper , the last question i don't think should have been 3 marks ... but I'm not complaining :biggrin:

Reply 1486

iMacJack

16

Original post by Tomilolaa

Yeah , I feel like they swapped marks around on that paper , the last question i don't think should have been 3 marks ... but I'm not complaining :biggrin:

Hey mate do you remember the values when you had to calculate Sxy on the one where you had to show Syy = whatever? Thanks bro

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Reply 1487

GarlicBread01

OP

11

For the question that asks what happens to the pmcc value when adding the new x and y values to the data, what was the reasoning behind it?

I put that correlation would decrease so the pmcc would increase (closer to 0) because the new x and the new y values were above the mean x and the mean y value. This suggests that the more rainfall gave more sunshine so does not show show negative correlation

(edited 7 years ago)

Reply 1488

Messi555

1

Original post by GarlicBread01

For the question that asks what happens to the pmcc value when adding the new x and y values to the data, what was the reasoning behind it?

I put that correlation would decrease so the pmcc would increase (closer to 0) because the new x and the new y values were above the mean x and the mean y value. This suggests that the more rainfall gave more sunshine so does not show show negative correlation

I ended up putting the same. Wonder if we will get credited or not.

Reply 1489

leestitt

2

Original post by Messi555

I ended up putting the same. Wonder if we will get credited or not.

I did the same

Reply 1490

Namita Gurung

16

Original post by GarlicBread01

For the question that asks what happens to the pmcc value when adding the new x and y values to the data, what was the reasoning behind it?

I put that correlation would decrease so the pmcc would increase (closer to 0) because the new x and the new y values were above the mean x and the mean y value. This suggests that the more rainfall gave more sunshine so does not show show negative correlation

That's what I put as well. The two values don't fit the trend of the other values which makes it less of a negative correlation so pmcc will be closer to zero.

Reply 1491

Tomilolaa

1

Original post by iMacJack

Hey mate do you remember the values when you had to calculate Sxy on the one where you had to show Syy = whatever? Thanks bro

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I'm sorry, my memory sucks ... I don't remember the numbers , I just remember how i answered them :P

Reply 1492

Ae1in

5

Original post by shir1902

That's the way I did it, but I think we misunderstood the question. The number was not selected twice, it was selected once. We were then supposed to find the probability that that value would be larger for Sarah/ Rebecca.

Hopefully enough of us did it this way that we will get two marks? I can't stand the idea that I lost 4 so easily. Damn. I should have listened to that little voice in my head that was complaining I was doing too much work for four marks.

Reply 1493

Lucymariexoxo

4

Original post by Mia66

that's so good to hear! I was just worried that the exam board will prioritise maths and place the module with the highest ums in maths

No, they will arrange the applied units to give you the best grades, don't worry :smile:

Reply 1494

Alec Siegert

2

Original post by JustOneLastTime

I got 17 aswell but I'm not sure if its right

I got 17.4 something, and rounded up to 18 people

Reply 1495

studentsixth

13

Original post by veldt127

UMS doesn't scale exactly with marks; the gap between 90-100 and 80-90 isn't necessarily the same.

It's almost always been 7 (sometimes 6 but not in years) so that's how it should be this year too

Reply 1496

hogree

15

Original post by ejk99

Can someone explain how to calculate Syy with sd and mean please?

What you had to do was write out the Standard Deviation Formula. You can work out SigmaY by multiplying the mean by the number of vlaues Because they tell you what the SD is, you only have one "unknown" and that is Sigma(Y^2). So, you work that out by rearranging. And then if you know that, you can just plug values into Syy Formula.

For 1 Mark though, an absolute disgrace.