ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: Vince2222 on March 23, 2013, 02:55:12 pm

Title: help (urgent )
Post by: Vince2222 on March 23, 2013, 02:55:12 pm
i am not sure if i am doing it right
http://www.mediafire.com/view/?n2qevgdx7ch5v65
-The first graph is a scatter box ,which means it is an linear
-Second graph is a residual plots which is a  random patten because the residual are randomly scattered above the x axis .This indicates it is an linear relationship .
The regression line is 1402.47*X+346.11
R=0.73
R^2=52%

-But if  i have to transform it would I have to uses    y-versus log10 (x)  formula
Title: Re: help (urgent )
Post by: Stick on March 23, 2013, 05:48:49 pm
This problem seems to be popping up a lot this year. You shouldn't have to transform a data set if it already appears linear and the residual plot shows no pattern. Check if you've made a mistake in entering your data.
Title: Re: help (urgent )
Post by: Vince2222 on March 23, 2013, 08:47:18 pm
hey thanks for the reply stick  :) going to double check now.But what  happen if my data is correct and should i reply to those question like this? -Their is no transformation  because the residual plot is a random patten and the residual are randomly scattered above the x axis .Also the scatter plot is already a linear.
Title: Re: help (urgent )
Post by: lala1911 on March 24, 2013, 01:16:21 am
Having the same issue..  :P
My graph is in a strong positive direction however all the transformations result in the regression line decreasing.. although part of the SAC tells us that we must apply a transformation to the data.

I actually think it doesn't matter if its stronger or weaker, because in my SAC we have to explain which scatterplot is more appropriate to use which I will say that the original one is better.
Title: Re: help (urgent )
Post by: Stick on March 24, 2013, 12:56:55 pm
Having the same issue..  :P
My graph is in a strong positive direction however all the transformations result in the regression line decreasing.. although part of the SAC tells us that we must apply a transformation to the data.

I actually think it doesn't matter if its stronger or weaker, because in my SAC we have to explain which scatterplot is more appropriate to use which I will say that the original one is better.

That's the only valid question they can ask in this case. Pretty pointless in my opinion, but schools can do what they want I guess.
Title: Re: help (urgent )
Post by: lala1911 on March 24, 2013, 01:08:40 pm
That's the only valid question they can ask in this case. Pretty pointless in my opinion, but schools can do what they want I guess.
Yeah. However I don't see the point in schools doing data analysis SACs as the exams are based primarily on chapters 1-4, while Data Analysis SACs are generally based on chapters 5-6 (of the Essential Further Mathematics textbook that is).

Title: Re: help (urgent )
Post by: Stick on March 24, 2013, 03:47:22 pm
Mine covered pretty much everything except time series data.