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Official Thread: OCR MEI S2/M1

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Original post by Studious_Student
I used "insignificant" instead of "not significant". Would I still get marks for the conclusion? Because apparently "insignificant" is not correct :O


Can I have more context? Do you mean after you've compared the critical value and test statistic, so you put "The result is not significant"?

If so, I doubt you'd actually lose a mark for that but they definitely prefer not significant.

But for the next part putting "insufficient" is allowed, in case you meant that.
Original post by ComputerMaths97
Which one are people talking about a continuity corrections?

I only remember is for the 650 one, where it was P(x >/= 650) = P(Z > (649.5-600)/s.d)


I used continuity corrections for the one where it asks for h fans that make up 99.9% of the fans that last longer or something. Don't know if I did it right though because I got a decimal.
Original post by Bealzibub
how many marks will i lose if i did everything else correctly? it was 11mark question .


What did you get wrong, did you just get the wrong variance?
Original post by Studious_Student
I used continuity corrections for the one where it asks for h fans that make up 99.9% of the fans that last longer or something. Don't know if I did it right though because I got a decimal.


That wasn't an approximation so I didn't use a continuity correction there, at least as far as I can remember :biggrin:
Original post by ComputerMaths97
Can I have more context? Do you mean after you've compared the critical value and test statistic, so you put "The result is not significant"?

If so, I doubt you'd actually lose a mark for that but they definitely prefer not significant.

But for the next part putting "insufficient" is allowed, in case you meant that.


Yeah I compared the critical value and test statistic but I said "The result is insignificant, we accept H0"
Original post by ComputerMaths97
That wasn't an approximation so I didn't use a continuity correction there, at least as far as I can remember :biggrin:


Damn, messed that up then lol, would I still get method marks?
http://www.mei.org.uk/files/pdf/spearmanrcc.pdf

Guys if you go to page 5, it says that there is no assumption for spearmans test (about the underlying distribution).. WHOOP :biggrin:
How many marks do you reckon you'll need for an A?
Original post by Olivia98hey
How many marks do you reckon you'll need for an A?


At least 60, probably about 62 though my guess
If anyone has the question paper, please could you PM it to me. TIA
Original post by ComputerMaths97
What did you get wrong, did you just get the wrong variance?
yes, i used population mean to work it out rather than sample mean, everything else 100% correct when taken wrong variance into accountAny idea?
Original post by Bealzibub
yes, i used population mean to work it out rather than sample mean, everything else 100% correct when taken wrong variance into accountAny idea?


Well you can't really say "everything else 100% correct" because if you got s.d wrong you lose 2 there. Then your test statistics is wrong, so it your conclusion. Would lose at least 5 depending on what else you got wrong. You can't expect to get most of the marks if your values are wrong unfortunately
I just saw the markscheme for a question I did wrong and they said to penalise any erroneous continuity corrections. Does that mean I won't earn any marks for the whole question and have 1 mark deducted even though I did the method right afterwards?

Also, I remember in the conclusion of my hypothesis tests I said that there is insufficient/sufficient evidence to suggest and conclude...would that be too assertive of a conclusion?
(edited 7 years ago)
Reply 133
Avatar for leaf3
leaf3
1
What did people do for the scale on the scatter graph, how much of the graph paper did it need to take up? :smile:
Original post by Studious_Student
I just saw the markscheme for a question I did wrong and they said to penalise any erroneous continuity corrections. Does that mean I won't earn any marks for the whole question and have 1 mark deducted even though I did the method right afterwards?


Yeah from my memory they're INCREDIBLY harsh on continuity corrections being wrong/ misplaced. But I'm sure it was only a 3 or 5 mark question so you could only realistically lose a few marks.
Original post by leaf3
What did people do for the scale on the scatter graph, how much of the graph paper did it need to take up? :smile:


I used pretty much all of the graph paper up, I can't quite remember but I think I did jumps of 20 and jumps of 10 (can't remember which was which though)
Reply 136
Avatar for leaf3
leaf3
1
Original post by ComputerMaths97
I used pretty much all of the graph paper up, I can't quite remember but I think I did jumps of 20 and jumps of 10 (can't remember which was which though)

Oh damn I only used about half, would that be very detrimental? :/
Original post by ComputerMaths97
Yeah from my memory they're INCREDIBLY harsh on continuity corrections being wrong/ misplaced. But I'm sure it was only a 3 or 5 mark question so you could only realistically lose a few marks.


Damn it, I didn't think I would be deducted marks... :frown: And would saying "to suggest and conclude" be too assertive as a hypothesis test conclusion? Sorry I'm bombarding all these questions lol but all these mistakes are now piling up and I don't think I can get that A now.
Original post by leaf3
Oh damn I only used about half, would that be very detrimental? :/


If I'm honest I can't remember how much I used, but as long as you picked the biggest possible scale that you saw as sensible you'll be fine.

Worst case scenario (I think, please remember I'm not an examiner xD) is you'd lose 1 for lack of specificity if your graph is too small.
Original post by Studious_Student
Damn it, I didn't think I would be deducted marks... :frown: And would saying "to suggest and conclude" be too assertive as a hypothesis test conclusion? Sorry I'm bombarding all these questions lol but all these mistakes are now piling up and I don't think I can get that A now.


You can't of expected to get all the marks mate head up :smile:

Conclude is a very assertive word, can you remember the whole sentence? If you can I can give you a better opinion there.

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