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VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: haygirl on October 31, 2010, 11:51:17 am

Title: Data Transformation
Post by: haygirl on October 31, 2010, 11:51:17 am
I don't get how to work out what one to use.. so i have the circle of transformations but within each section there are a few different ones to use... How do i work out what one to use without putting it all into my calc? Sometimes not given enough info to be able to put it into the calc at times...

Thanks
Title: Re: Data Transformation
Post by: TyErd on October 31, 2010, 11:57:20 am
there all fine but if you were to choose one, you have to find out the transformation that gets you the highest correlation coefficient.
Title: Re: Data Transformation
Post by: haygirl on October 31, 2010, 12:18:11 pm
Say its a multi choice question and a few of them are options... how do i know?
Title: Re: Data Transformation
Post by: TyErd on October 31, 2010, 12:38:44 pm
if it asked which transformations were possible, then only one of those possible transformation will be an option, not all of them.  If it asked whats the most appropriate transformation, then you would have to find the correlation coefficient for each transformation, the highest one is the most appropriate.
Title: Re: Data Transformation
Post by: onerealsmartass on October 31, 2010, 12:43:19 pm
usually they would provide you with some information and sometimes a graph.
Compare the graph to the ptoential transformation graphs.
Whichever graph appears to be the most similar use that transformation, but sometimes there may be a better transformation - look at the correlation coefficient like TyErd said
Title: Re: Data Transformation
Post by: _avO on October 31, 2010, 12:45:43 pm
Earlier today I was doing an old Kilbaha exam there was one of those Multiple choice questions with transformations, and 3 of the 5 options were applicable however there were no values given so I had to guess (got it wrong).. This better not happen in the actual exam
Title: Re: Data Transformation
Post by: onerealsmartass on October 31, 2010, 01:01:29 pm
yeah that would suck.. but i dont think vcaa will do that, it has to be fairly straightforward and simple
Title: Re: Data Transformation
Post by: haygirl on October 31, 2010, 01:30:53 pm
I was doing a VCAA one and it had a graph and then had the options but there was more than one of the options that would fit.. but not enough info was giving to be able to put it into my calc to work it out... so yeah
Title: Re: Data Transformation
Post by: _avO on October 31, 2010, 01:49:09 pm
If I may, which exam were you doing? I wanna check it out
Title: Re: Data Transformation
Post by: TyErd on October 31, 2010, 01:57:58 pm
yeah same
Title: Re: Data Transformation
Post by: haygirl on October 31, 2010, 02:20:52 pm
2009

The core question 12
Title: Re: Data Transformation
Post by: _avO on October 31, 2010, 02:24:48 pm
All you need to do is roughly estimate each point on the graph, plot it in your calculator, produce a transformation and determine the highest r value. Yes it may take some time but the previous questions are most likely quick and easy

EDIT: After looking at that question closely, there is only one answer possible which is C. Correct me if i'm wrong
Title: Re: Data Transformation
Post by: haygirl on October 31, 2010, 02:38:55 pm
C is correct....

So u think the best way to go about is it so put it roughly into the calc and go from there?
Title: Re: Data Transformation
Post by: _avO on October 31, 2010, 02:42:24 pm
No if you read it, it says mathematics against internet usage. This represents y vs x
The transformations possible for this graph are:

y^2 vs x
y vs log(x)
y vs 1/x

Now if you refer back to the possible answers, only C (mathematics against log(internet usage)) applies so therefore thats the only answer, no calculations necessary
Title: Re: Data Transformation
Post by: haygirl on October 31, 2010, 03:06:49 pm
Thanks i can see it now.... :)
Title: Re: Data Transformation
Post by: TyErd on November 01, 2010, 08:46:33 am
anyone else see a problem with neap 06 question 10?