VCE General & Further Maths Question Thread!

[Kimahso]

Hi everyone,

I understand that postcode is a categorical variable, however, is it nominal or ordinal? Can you please explain why?

Thanks!

According to the 2016 VCAA Sample Exam it's nominal although according to the ABS website it's ordinal (which makes sense IMO).

[clarke54321]

According to the 2016 VCAA Sample Exam it's nominal although according to the ABS website it's ordinal (which makes sense IMO).

Hmm…. That's interesting. Well, if VCAA say it's nominal then I better go with nominal.

Although, it does make sense for it to be ordinal.

[Cornrow Kenny]

According to the 2016 VCAA Sample Exam it's nominal although according to the ABS website it's ordinal (which makes sense IMO).

My bad! I can see the arguments for both 

[AhNeon]

How about age? Is it discrete or continuous cos ive seen questions with differing answers

[ayesha2011t]

My bad! I can see the arguments for both 

What's your argument for it being categorically nominal?

[RuiAce]

How about age? Is it discrete or continuous cos ive seen questions with differing answers

If you're going to round to, say, the nearest year, then it is discrete.

Age is technically continuous as you can be, say, 40.28154353163 years old

[Cornrow Kenny]

What's your argument for it being categorically nominal?

I'm leaning to ordinal, someone who thinks it is nominal would probably argue better than me.

I guess you could argue that you can't really put locations in order, as that is what postcodes represent.

[clarke54321]

I'm leaning to ordinal, someone who thinks it is nominal would probably argue better than me.

I guess you could argue that you can't really put locations in order, as that is what postcodes represent.

I agree. I wish VCAA would provide their justification as to why it is nominal.

[MightyBeh]

Total guess but could it be that postcodes act as 'labels' for certain areas? Particularly on a map or for postage (like 7000 -> Middle of nowhere, Tasmania). I think either Nominal or Ordinal are reasonably valid assertions. Unless it changed this year the distinction between types of categorical data isn't important anyway, yeah?

[TooLazy]

  This a question from the sample exam issued:

"There is an association between the variables population density, in people per square kilometre, and area, in square kilometres, of 38 inner suburbs of the same city.
For this association, r^2 = 0.141"

This is the solution:

population density = population/area , inverse relationship
between population density and area, .: r = − sqrt(0.141) ≈ − 0.375

So basically, what does it mean by inverse relationship. Our textbook never really explained that. Also how can you tell if the r value is negative or not since there is no scatter plot to determine it.

[clarke54321]

This a question from the sample exam issued:

"There is an association between the variables population density, in people per square kilometre, and area, in square kilometres, of 38 inner suburbs of the same city.
For this association, r^2 = 0.141"

This is the solution:

population density = population/area , inverse relationship
between population density and area, .: r = − sqrt(0.141) ≈ − 0.375

So basically, what does it mean by inverse relationship. Our textbook never really explained that. Also how can you tell if the r value is negative or not since there is no scatter plot to determine it.

Hey,

I questioned this too!! It's so odd, I've never seen a question like this without the actual scatterplot or some further information.

[TooLazy]

Hey,

I questioned this too!! It's so odd, I've never seen a question like this without the actual scatterplot or some further information.

Same!
And I couldn't find anything in my textbook related to 'inverse relationships'.

[MightyBeh]

I believe inverse relationship is the same as reciprocal; it should be in your textbook in the transforming data part. It might not be explicitly mentioned, though. If you think of area as the IV and call it x, it might be a little more intuitive. The relation 1/x will be smaller for larger values of x (edit: Implying that if you were to model it with a line it would have a negative slope); 1/6 is less than 1/3, and so on. Correct me if I'm wrong though, it seems like a pretty odd question imo.

[TooLazy]

If you were calculating total interest paid, if there are 30.8 payments for example,
would you multiply 30.8 by the payment amount. Or would you round it up to 31 first?

[ayesha2011t]

Can someone pls explain this question to me? Correct answer is B
thanks!