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AQA M1SB 8th of june 2016 unofficial markscheme

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Original post by Dapperblook22
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.

Thanks well now i need to bang out FP1 and D1 for further maths. The optimum least(yeah i don't think that sounds right) i got for this paper is 55. 20 WHOLE marks lost 😩😩😢
Original post by OfficialChemist
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


you see i worked out the standard error and then used this in the equation for interval and so my confidence interval was all within 300. so after converting i got that 400 was above my confidence interval and was invalid. but my friends didnt put standard error wher sd would go in the formula and so they got that the claim was valid
Original post by clairebear101
you see i worked out the standard error and then used this in the equation for interval and so my confidence interval was all within 300. so after converting i got that 400 was above my confidence interval and was invalid. but my friends didnt put standard error wher sd would go in the formula and so they got that the claim was valid


Ahh yeah yeah, i used standard error as well for the CI
Original post by OfficialChemist
Ahh yeah yeah, i used standard error as well for the CI


so u got the standard error of 23.3(or whatever) and then put this in the sd/root n part of the formula? this is what i did, do u think we did it right? my friends jsut used the S value given in the question and got an interval of (253,377) which seems massive?
A few main questions.

What did you say that the assumption was for part c?

What did you get for the probability that it wouldn't be a particular value on the normal distribution (normally you say 100% if it's the mean, but in this case I did something else)

Who else hopes the grade boundaries are lower than a donkey's testes?
Does anyone remember the exact wording of question 3 as well as the sub-questions of question 3 ... People after putting down answers to question 3 and i don't reject the answers i got
Original post by moinul98
It was actually £166.6666... which is < 166.67, I think they did that to catch us out.


yes but when using pounds you round to two dp and so using 166.67 should have been correct so i dont know what they will put as the answer, this question was unfair
Original post by TIF141
Wasn't it 8/40 as one was exactly 166.67 which is 200/1.2? And I think it said 'at most 200', which includes £166.67?


Well it was 8 but I don't think your reasoning is correct, It's cause 200/1.2 = 166.66..7 which is < 166.67, that's what my thought process was but I don't think it matters
Original post by clairebear101
so u got the standard error of 23.3(or whatever) and then put this in the sd/root n part of the formula? this is what i did, do u think we did it right? my friends jsut used the S value given in the question and got an interval of (253,377) which seems massive?


I did [Mean-2.58*SE, Mean+2.58*SE]

Where SE is the Standard Error

then for the justification, i times both values by the conversion rate of pounds to euros, then had a new CI, then did my explanation etc
Original post by moinul98
Well it was 8 but I don't think your reasoning is correct, It's cause 200/1.2 = 166.66..7 which is < 166.67, that's what my thought process was but I don't think it matters


yes but 166.67 times by 1.2 = 200.004 which is greater than 200 and so should not be counted
Original post by OfficialChemist
You'll probably only lose 1 mark cos you've understood the method tbh


I hope you're right! :biggrin:
Original post by OfficialChemist
I did [Mean-2.58*SE, Mean+2.58*SE]

Where SE is the Standard Error

then for the justification, i times both values by the conversion rate of pounds to euros, then had a new CI, then did my explanation etc


erg i did this but then i changed it :/ i did the standard error before the equation and then used the standard effor in the equation for where the standard deviation was. After this i did the same methid as u and then got the it was invlid. I dunno how many marks i will looose
Original post by clairebear101
yes but 166.67 times by 1.2 = 200.004 which is greater than 200 and so should not be counted


I'm not sure, but does it matter if you include a specific fraction or not?

I just said that the claim was valid (claim 2 btw) as for the first 25% of customers (the first row) the highest value was greater than €200 and, therefore, less than 25% of customers would've spent €200. Hence, the claim that "at most" 25% spent less than €200 is correct.

Let me know if I'm wrong on this one.
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Original post by OfficialChemist
4 Marks if i recall correctly


How many marks do you think Iwould lose if I used z as 2.33 but did the rest right?
Original post by Thequickspark
I'm not sure, but does it matter if you include a specific fraction or not?

I just said that the claim was valid (claim 2 btw) as for the first 25% of customers (the first row) the highest value was greater than €200 and, therefore, less than 25% of customers would've spent €200. Hence, the claim that "at most" 25% spent less than €200 is correct.

Let me know if I'm wrong on this one.


i think there were many ways to prove this but the main message is that it was incorrect anyway if i only lost most my marks on the last question then i should still get an A, any grade predictions?
Original post by clairebear101
erg i did this but then i changed it :/ i did the standard error before the equation and then used the standard effor in the equation for where the standard deviation was. After this i did the same methid as u and then got the it was invlid. I dunno how many marks i will looose


If you did it properly at the end you should get full marks tbh, that's provided we're both correct lol
What did you get for the accuracy for -7/+9 residuals one?
Original post by OfficialChemist
If you did it properly at the end you should get full marks tbh, that's provided we're both correct lol


i dunno as cuz i basiclalt used s.e twice, once i worked it out before and then i used it again in the equation but ah well i will get all the method marks and so should only loose 3 or so marks, not the end of the world
Original post by goofyygoober
What did you get for the accuracy for -7/+9 residuals one?


I said large residuals meant that the estimate was likely to be inaccurate, but still reasonable enough.
Original post by goofyygoober
What did you get for the accuracy for -7/+9 residuals one?


7 and 9 were very samll comapred to the y values which were in the hundreds so i said it was accurate and could also be an overestimate

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