Re: Plotting exercises for next Monday

[Paul Johnson <>]

How about predicting school child IQ test averages as a function of 
sugar in the diet. In one country, more sugar correlates with higher 
scores. In another country, more sugar leads to lower scores. In 
another, there is not relationship.

pj

linseym wrote:
> Prof. Johnson, Please advise: I understand how to change the constant and the 
> slope in order to change the line, however I am having extreme difficulty 
> coming up with a real world situation for these three lines.  My first problem 
> comes because most graphs I have done have would have three cities with three 
> diff. (x,y)-representing values of two variables- and then you would plot 
> these three points, draw a line through them to show the relationship of the 
> two variables.  The problem comes in my brain when there is three lines, 
> should I try to think of each country as their own line?  The only way I can 
> think to make this work is to have the x-axis be time and so to show change 
> over time.  Is this what you were thinking.  Please help, Linsey


--
Paul E. Johnson                       email: pauljohn_AT_ku.edu
Dept. of Political Science            http://lark.cc.ku.edu/~pauljohn
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