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Here is a couple of paragraphs about Regression Lines and Linear Equations in graphs. It concludes with

A line that “best fits” the data can then be drawn through the scatter diagram. This line is called the regression line, and it can be used to produce a linear equation, y = bx + a, that describes the approximate relation between IQ score (x) and GPA (y).

I can follow everything up until the "a". What would be the value of it here, and what could it be representing?

Thank you!

Matha Maticallycha Llenged

a few paragraphs about the main idea

Dibliander3000
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1 Answers1

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$a$ is the $y$-intercept.

It is the predicted value of $y$ when $x=0$, that is the GPA when the IQ is $0$.

Siong Thye Goh
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  • Can't quite follow. Can you illustrate at all? – Dibliander3000 Nov 30 '22 at 09:13
  • $y=bx+a$ is a straight line (the blue line), here $a$ and $b$ are value that would determine the line. $b$ is the slope and $a$ is the intercept. If the IQ is $100$, then the GPA is predicted to be $100b+a$. If the IQ is $50$, then the GPA is predicted to be $50b+a$. If the IQ is $0$, then the GPA is predicted to be $0\cdot b + a=a$. – Siong Thye Goh Nov 30 '22 at 09:29
  • VERY grateful! THANK YOU!! :))) – Dibliander3000 Nov 30 '22 at 10:02