Graphing Data
Key Questions

Answer:
Se explanantion
Explanation:
Consider the equation
#y=mx+c# You can give any value you chose to
#x# and the value of#y# depends on what value you give to#x# So
#y# is the dependant variable and#x# is the independent variable.What you looking for is this: if the independent variable only maps to one value in the dependant variable then the equation/graph is that of a function.

Well, this is a difficult one! I am not sure this is going to help, but I try anyway.
When I have to analyze a phenomenon (I am a physicist...!) I collect data that characterize the phenomenon (for example, I measure the height of a kid each week) and then I plot them.
The result is a graph with points on it that hopefully shows a "tendency".
This can be a linear tendency, for example, so that I can use a line to represent them (the line that "best fit" all the data points).
Next I evaluate the equation of the line in the general form:#y=ax+b# Now, even if I do not know what happens for a certain value of the variable
#x# (because I didn't measure it directly) I can put it in the equation of the line and get the corresponding value for#y# .In the example of the height of a kid, I can measure it along, say, a period of 5 weeks, get my graph and evaluate the linear equation as:
#height=2*time+40# in cm for the eight and week for the time (2 will have units of cm/week and 40 of cm).If I want the height of the kid in the 7th week I put time=7 and find the projected height.
Remember:
You can have different curves that fit your data (parabolas. hyperbolae, sinusoidals...);
The fit depends upon the "goodness" of you experiment in the first place. If you try to correlate the height of a kid to the number of red cars you observe ...it won't probably work very well!
(hope it helps!)

To visualize it (and eventually, for example, to find out patterns in the data that otherwise would be hard to find).