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AQA M1SB 8th of june 2016 unofficial markscheme

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• View Poll Results: [AQA MS1B 8th of June 2016] What raw mark do you think the A grade will be ?
66
20.00%
65
5.00%
64
10.00%
63
8.33%
62
13.33%
61
11.67%
60
15.00%
59
5.00%
58
11.67%

1. (Original post by Thequickspark)
Yeah, that's exactly what I would've done. I must've made a mistake on something alone the way. Thank you for explaining!
It's all bless, btw do your other answers match mine by any chance?
2. (Original post by Dapperblook22)
Did you use the calculator or tables to find the probability?
Tables I believe.
3. By the way what was the assumption made, I said that the probability either side of the mean was 0.5 because even if something is normally distributed it sometimes isn't.
4. (Original post by Parhomus)
By the way what was the assumption made, I said that the probability either side of the mean was 0.5 because even if something is normally distributed it sometimes isn't.
I said the assumption is that the volumes are a random sample, as this answer also appeared in the Jan 2008 paper.
5. (Original post by Parhomus)
For question 7 wasn't the second claim valid since 20% had spent less than 200 euros and it said at most 25% spent 200 or less.
i got that 17.5% were lowet than 200 euros and so claim is valid
6. (Original post by Thequickspark)
Tables I believe.
So did I, you may have just looked at the wrong value either side of the correct one in the table, which is a mistake I have made a few times before
7. (Original post by Kloopz)
I got this as well
it wasnt 20% is was 17.5% since it was LESS than 200 euros and so u didnt enclude the person who had spent 167.67 pounds
8. (Original post by Dapperblook22)
I worked out the probabilty of 1 bottle containing the amount required, which is 0.841, so the probability of all 6 is 0.841^6 = 0.354
is this for the in "each" part of the question
9. (Original post by Dapperblook22)
it wasn't the first 10, as otherwise you would be comparing pounds to euros. You had to either convert the euros to pounds, or the pounds to euros and then find that it was 7/40 entries.
i got 7/40 as well
10. (Original post by Dapperblook22)
So did I, you may have just looked at the wrong value either side of the correct one in the table, which is a mistake I have made a few times before
Yeah, things like this happen when you're under time conditions and stress I suppose. Oh well, hopefully the boundaries will allow for me to lose 10 -12 marks and still get an A.
11. (Original post by Dynamic_Vicz)
is this for the in "each" part of the question
I think so, 'cause the other part of the question was about the distribution of the means, where you wouldn't need to raise to a power.
12. (Original post by Parhomus)
Yes
no it said less than 200
13. (Original post by OfficialChemist)
10% Contain more than 1535, so you're looking at the 90th percentile. Finding the Z value for this gives 1.28. You then sub this into the standardising formula to work out the new mean. The new mean ends up as being 1522.712. As it wants the difference, you do:

1525-1522.712
= 2.288
=2.3
14. (Original post by OfficialChemist)
10% Contain more than 1535, so you're looking at the 90th percentile. Finding the Z value for this gives 1.28. You then sub this into the standardising formula to work out the new mean. The new mean ends up as being 1522.712. As it wants the difference, you do:

1525-1522.712
= 2.288
=2.3
I just worked out where I went wrong. I must've put 1.218 as my value for 90% rather than 1.28....

So annoying haha
15. (Original post by SM-)
4 Marks if i recall correctly
16. (Original post by Thequickspark)
I just worked out where I went wrong. I must've put 1.218 as my value for 90% rather than 1.28....

So annoying haha
You'll probably only lose 1 mark cos you've understood the method tbh
17. (Original post by OfficialChemist)
Here's a few of my answers:

R=0.959
Mode = 26
IQR = 2

The 2 things were mean and SD

then Mean = 25.6
SD= 5.26

Equation of regression line was
y=181+3.00x
For the interpretation of gradient, i said that as the temperature increases by 1 degrees celcius, the mass of whatever dissolved etc increases by 3.00g
the estimation was 385g
i said large residuals so unreliable

then the probability questions i got
0.352
0.136
0.158
0.792
0.267
and the 5 marker probability i got 0.0205

The normal distrubuition ones i got
0.941
0.149
0.792
0.354
0.993

and the reduction in mean i got 2.3

The 4 marker binomial one i got 0.891

For the last question i disagree with first claim as after u make the new CI with the values in euros, 400 wasnt within the new CI, so claim was invalid.
The second claim which working out the eurors to pounds conversion gave 166.67, and it wanted less than that, i got 14% and i said that therefore claim is not true.
So first claim = invalid
Second claim= Invalid

and that's about it for all i remember/wrote down on extra paper i asked for.
What did u get for your confidence interval? everyone i got said the claim was valid but i said it was invalid :/
18. Mark distribution for questions: (Copied from my calculator)

1: 3,2
2: 1,2,2,3
3: 9,5
4: 4,2,1,2
5: 7,4,7
6: 2,1,3,4,2
7: 4,5

2a i) Mode = 26
ii) mean (25) and IQR (2)
b i) 2 things you can't find out: (mean, SD, range)
ii) mean: 25.6, SD: 5.26

3a) 0.352, 0.136, 0.158, 0.792

4) 181.3, 3, 386

5) There was a 100% probability in there...
19. (Original post by clairebear101)
What did u get for your confidence interval? everyone i got said the claim was valid but i said it was invalid :/
I think my value was less than the confidence interval so it was invalid, if you remember the CI in pounds, i can convert it to euros and tell u exactly, but whatever it was, the claim was definitely invalid as it wasn't within the CI
20. (Original post by Dapperblook22)
it wasn't the first 10, as otherwise you would be comparing pounds to euros. You had to either convert the euros to pounds, or the pounds to euros and then find that it was 7/40 entries.
****, oh well.
(Original post by xs4)
Q3) probabilities - different ages and bands 1-3ai) 0.136ii) 0.158iv) 0.729v) I can't remember [9 marks for part a]b) 0.0308 [5 marks]
question part v)

2 out of 4: age band 45 - (something) and not band o
and the other 2 out of 4 aged 66 & over and in band 1 & 2

I think the 45 bracket totalled to 146 on the table
and the 66+ bracket to 176.

b) P(1515?<X<1540)
yes it is 1515 i remember cause it looked like ISIS

Q6) Normal distribution
volume of the bottles in a pack of 6
mean 508.5 , SD= 9.6?
ai) P(X>505) [NOT SURE IF THIS IS ACTUALLY ai)]
i) P (x<504) for each of the 6 water bottles.
ii) what is the probability when the mean volume of 6 bottles is more than 504

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