Question 637541
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The normal convention is to make the "one quantity" the vertical axis and the "another quantity" as the horizontal axis.  In correct terminology, your "one quantity" is the dependent variable and the "another quantity" is the independent variable.  The value of the dependent variable, being expressed in terms of the independent variable, is dependent upon the value of that independent variable...hence the name.


Depending on the story you are trying to tell, the dependent and independent variables may change roles.  For example, suppose you wanted to investigate the relationship between the number of hours spent playing video games and a student's grade point average.  You might ask the question, "How does a student's grade point average vary as a function of how many hours a day the student spends with the X-box."  In this case, the independent variable is the number of hours with the game, and should be plotted on the horizontal axis.  The dependent variable, grade point average, would be plotted on the vertical.  But what if you reversed the question.  "What does a person's grade point average say about the number of hours spent playing with the Wii?"  Here you would want to look up, across the horizontal axis, a particular grade point average, and see how many daily video game hours were being logged by people in that category.


John
*[tex \LARGE e^{i\pi}\ +\ 1\ =\ 0]
My calculator said it, I believe it, that settles it
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