# June 2013 S3 Questions

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#1
Hello everyone,

I've got a few questions regarding some questions I attempted from a past paper. Some of them occur frequently, so I just want to get rid of any problems or doubts I have in my mind.

Attachment 743378

For this question, if I labelled the males as 1-300 and the females are 301 - 400, instead of 1-100, would I lose any marks?
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#2
For this question, (Q4).
Though I done very good on the paper, I felt that these questions were slightly different to what I've seen and I just want to make sure I get my understand right.

For part (d), it asks whether or not the proportions of people in the population with black, brown, red and blonde hair are in the ratio 21:3.
So, does that mean since the only variable in question is the hair colour - we ignore the other variable (eye colour) and focus on only the hair colours and do a chi-squared test on that.
So, by working out the expected frequencies through the ratios etc. - I got the question correct and achieved full marks. I know how to perform the test exactly, but I was unsure how to approach the question.
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#3
For this question (Q5),

for part (b), since the circumference of a circle = 2πr = πd. I could multiply the diameter by pi to work out the circumference. However, it's obviously that is all that is required for 1 mark, but how would I know I would just have to multiply it by 2? Since this is asking for a confidence interval, can someone break it down for me please?
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#4
For this question,

for part (b).

This is my working out, I just ticked it because I got the answer right lol.
Can someone please confirm if my working out is like worthy of the full marks please?

Thank you .

Attachment 743400
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#5
Thank you everyone for your continuous support in helping me achieve success .
I really appreciate it.

P.S. I done very good in this paper, all these questions I'm just asking to clear doubts in my mind - as I may have got them right today, and maybe wrong tomorrow.
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#6
(Original post by Chittesh14)
For this question,

for part (b).

This is my working out, I just ticked it because I got the answer right lol.
Can someone please confirm if my working out is like worthy of the full marks please?

Thank you .
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#7
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2 years ago
#8
Well that's a whole lot of text I can't be bothered to read at half 10!

Maybe tomorrow
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#9
(Original post by RDKGames)
Well that's a whole lot of text I can't be bothered to read at half 10!

Maybe tomorrow
No worries, thank you .
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2 years ago
#10
(Original post by Chittesh14)
Hello everyone,

I've got a few questions regarding some questions I attempted from a past paper. Some of them occur frequently, so I just want to get rid of any problems or doubts I have in my mind.

Attachment 743378

For this question, if I labelled the males as 1-300 and the females are 301 - 400, instead of 1-100, would I lose any marks?
Your method looks fine to me, as long as you made it clear that the random numbers for the second group would be in the range 301 to 400. (Caveat: I'm not an examiner).
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2 years ago
#11
(Original post by Chittesh14)
For this question, (Q4).
Though I done very good on the paper, I felt that these questions were slightly different to what I've seen and I just want to make sure I get my understand right.

For part (d), it asks whether or not the proportions of people in the population with black, brown, red and blonde hair are in the ratio 21:3.
So, does that mean since the only variable in question is the hair colour - we ignore the other variable (eye colour) and focus on only the hair colours and do a chi-squared test on that.
So, by working out the expected frequencies through the ratios etc. - I got the question correct and achieved full marks. I know how to perform the test exactly, but I was unsure how to approach the question.
The key phrase in the question is "in the population". That tells you you're dealing just with the Total row in the given table.
0
2 years ago
#12
(Original post by Chittesh14)
For this question (Q5),

for part (b), since the circumference of a circle = 2πr = πd. I could multiply the diameter by pi to work out the circumference. However, it's obviously that is all that is required for 1 mark, but how would I know I would just have to multiply it by 2? Since this is asking for a confidence interval, can someone break it down for me please?
If the diameter (mu) is 118.8, then the circumference is 118.8 x pi. If the diameter is 121.2, then the circumference is 121.2 x pi. There is nothing more to this part of the question.
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2 years ago
#13
(Original post by Chittesh14)
For this question,

for part (b).

This is my working out, I just ticked it because I got the answer right lol.
Can someone please confirm if my working out is like worthy of the full marks please?

Thank you .
Not sure about this one, but I think you are skating on thin ice in not explicitly stating the relationship between mu and a. The "-1 M" you've awarded yourself is probably wise during revision.
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#14
If anyone else wants to give their insights or different approaches to any of the questions, please share your knowledge with me . RDKGames Gregorius Notnek. Can someone also confirm the doubts with the methods please? Thank you.

(Original post by old_engineer)
Your method looks fine to me, as long as you made it clear that the random numbers for the second group would be in the range 301 to 400. (Caveat: I'm not an examiner).
Thank you, yeah I would label the females in the range 301 - 400, so I think it's fine - as long as it's labelled right? Just wanted to make sure :P.

(Original post by old_engineer)
The key phrase in the question is "in the population". That tells you you're dealing just with the Total row in the given table.
What do you mean? Do you mean the different hair colours?

(Original post by old_engineer)
If the diameter (mu) is 118.8, then the circumference is 118.8 x pi. If the diameter is 121.2, then the circumference is 121.2 x pi. There is nothing more to this part of the question.
Oh, I thought there was more than that . Thank you so much . Because you know sometimes those sneaky 1 markers have require some serious underlying knoweldge that tests you, though it wasn't in here - though it might have been.

(Original post by old_engineer)
Not sure about this one, but I think you are skating on thin ice in not explicitly stating the relationship between mu and a. The "-1 M" you've awarded yourself is probably wise during revision.
Yeah, I don't really know how to gain the method marks and make my working out clear etc. So I just wanted it clarified.

Thank you for all your support and contribution to my questions, I really appreciate it .
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