ATAR Notes: Forum

VCE Stuff => VCE Mathematics => VCE Mathematics/Science/Technology => VCE Subjects + Help => VCE General & Further Mathematics => Topic started by: Yendall on November 04, 2012, 01:12:10 pm

Title: Core Question - apologies for my ignorance
Post by: Yendall on November 04, 2012, 01:12:10 pm

(http://s18.postimage.org/o1tba0yyh/Untitled_2.jpg)

For this part, it asks to apply the reciprocal transformation to the data and determine the equation. Then it states "Write the coefficients correct to two decimal places"

Now either this is a simple misinterpretation or i'm missing something.
This is what I did:

Transformed the data:

(http://s8.postimage.org/atc73duxx/Transformed_data.jpg)

Plotted the transformed data as X-Reciprocal and Y:

(http://s8.postimage.org/exhr9mg9x/Transformed_data_2.jpg)

Determined the coefficients:

(http://s17.postimage.org/apv0fy073/Transformed_data_3.jpg)

I know why this is wrong, they are asking for the equation. But, can $a, b, m, x, y$ be seen as "coefficients"? Whenever a question like this appears, when they ask for "coefficients" do you automatically assume it's the regression equation? or $r$ and $r^2$ ?

Title: Re: Core Question - apologies for my ignorance
Post by: StumbleBum on November 04, 2012, 01:35:57 pm

Quote from: Yendall on November 04, 2012, 01:12:10 pm

I know why this is wrong, they are asking for the equation. But, can $a, b, m, x, y$ be seen as "coefficients"?

Since when can $x$ and $y$ ever be considered coefficients when talking about a regression line? And $m$ will be the same as $b$ because that's what the gradient is. Although I don't know where you got $m$ from as your calculator doesn't refer to the gradient as $m$ ?

Quote from: Yendall on November 04, 2012, 01:12:10 pm

when they ask for "coefficients" do you automatically assume it's the regression equation? or $r$ and $r^2$ ?

I don't get how you are interpreting it like this... In the question it asks you to determine the "least squares regression line", so it is that exact phrase that makes you automatically assume they want the regression equation.

And seen as they are not referring to strength or the relationship (in terms of whether the variation in DP depends on the IV) then why would you ever consider mentioning the $r$ and $r^2$ values?

Title: Re: Core Question - apologies for my ignorance
Post by: Yendall on November 04, 2012, 01:38:53 pm

Thank you! I just over-thought and misinterpreted the question.