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# Edexcel s1 June 2016 unofficial mark scheme Watch

1. I said mean stays the same and then gave an explanation that this was because the new value was equal to the mean.

I said that s.d would stay the same as it is 0 deviations above the mean (I know this part is wrong)

How many marks would I get it? The question was out of 3
2. I also got r = -0.753 because I used the calculator value of Syy (716 with decimals) and not the given value of Syy (716 to 3sf)

Lose marks or nah?
3. (Original post by Zakariya121)
I reckon 55 for an A
We are talking about Edexcel here
4. For the height of the bar, wasn't the A = 4*F ???
5. (Original post by ShatnersBassoon)
But the new value was exactly the same as the mean, so the SD (average distance from mean) can't increase. Others said it stayed the same, but I wrote that it decreases, because now the average distance from the mean is slightly less (as n has increased by 1 but deviance hasn't changed).
It definitely decreased because the data will be less spread out.
I said mean stays the same and then gave an explanation that this was because the new value was equal to the mean.

I said that s.d would stay the same as it is 0 deviations above the mean (I know this part is wrong)

How many marks would I get it? The question was out of 3
The standard deviation tells you on average how far the values are away from the mean so since the new value was zero away from the mean the average spread would decrease you probs got one mark for the mean part
7. Crap was the question for the one below the histogram (w>3) or (w<3) cos I got 0.7.... ??
8. (Original post by Azim101)
Crap was the question for the one below the histogram (w>3) or (w<3) cos I got 0.7.... ??

um.. p(w <3 )
9. (Original post by igotohaggerston)
The standard deviation tells you on average how far the values are away from the mean so since the new value was zero away from the mean the average spread would decrease you probs got one mark for the mean part
Was it out of 3 marks?
10. can someone post the question paper
11. will anybody be getting hold of the paper and doing worked solutions
Was it out of 3 marks?
I thought it was 2? 1 mark for each. I hope it isn't 3
13. (Original post by target21859)
I thought it was 2? 1 mark for each. I hope it isn't 3
If it was 2 marks that would be brilliant. Can anyone confirm how many marks was it out of?
14. can someone reply to me with the model answers similar in the format of a exam paper.

Like how some are done for other modules.
If it was 2 marks that would be brilliant. Can anyone confirm how many marks was it out of?
1 mark for mean and 2 for SD
16. (Original post by PhilipBlanksky)
1 mark for mean and 2 for SD
crap
17. how many marks will get you an A ? anyone has any guesses
18. (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:
Show
a. Show that
b. W - can't remember reasoning
c. 0.994
d. 0.0772 + 0.0142d
e. i. 5.69
ii. Reliable as the data was interpolated; it was within the range
Question 2
Spoiler:
Show
a. 2p + q = 0.5
b. q = 0.15
c. p = 0.175
d. 2.12
e. 0.45
f. i. 0.475
ii. 0.375
Question 3
Spoiler:
Show
a. 2.35
b. Show that
c. -133.9 - possibly -131.9
d. -0.754
e. Increase - I tried using the variables from the new week and recalculating r, and it was higher than the original. I said because the values were both higher than the means; I'm not sure at all on this one.
Question 4
Spoiler:
Show
a. 0
b. t = 0.03
c. u = 0.22
d. i. 0.45
ii. 15/37
e. 33 people have dinner (40*0.18) + (37*(15/37))
Question 5
Spoiler:
Show
a. Width 0.5, Height 17
b. 3.47 (median)
c. i. Show that
ii. Standard deviation = 0.680 - possibly 0.689
d. P(W<3) = 0.2546
e. No - the mean is not equal to the median suggesting asymmetrical skew18% of babies were less than 3kg, but her model predicted 25.46%
f. i. Mean remains the same as the new value is the mean
note: mean might decrease as it adds a value to the 3-3.5 group.
ii. The standard deviation decreases as the variance decreases with a new value close to the mean
Question 6
Spoiler:
Show
a. 0.0668
b. 206 - The lowest 20% of times were the fastest 20% of runners.
c. 0.36
For the height of the bar, I thought the coefficient between f and A was 4. A=4*f or the otherway round maybe
19. (Original post by PhilipBlanksky)
1 mark for mean and 2 for SD
It seems I keep losing marks... First I thought I had 71 now it's more like 64. Probably less cause I left my my values for PMCC and standard deviation to 2dp (for some really annoying reason) and I'm not really confident I'll get the marks...
20. How did everyone get the probability for Sarah and Rebecca wining. I got 0.4625 and 0.4450 so clearly I've got it wrong but I don't understand how?? 🤓🤓

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