what decides the placement of a variable on X or Y axis?

Question

in plotting a relationship between 2 variables one of the variable is put on Y axis & other on X axis so can they be reversed & if not then what criteria decides which variable is to be put on which axis?

Answer 1

There are traditions, but they can be broken.



If plotting x and f(x), e.g. sin(x), its normal to put x on the x axis of course, but its not wrong to do it the other way. However, you will hardly ever see this.



Time is usually plotted on the x axis.

Input variables are often on the x axis.



Suppose you had to plot height verses weight. The Y axis might comfortably take the height figures for obvious reasons.



I've made a tide chart recorder system using fanfold paper on a dot matrix printer. On this graph it made sense to have the time axis parallel to the edge of the continuous run of paper, and tide heights plotted across the sheet ("X" direction.)

Answer 2

It's a convention. Any graph showing the relationship between two variables is a visual represention of how one phenomenon (called the *dependent* variable) will change as a result of alterations to the other phenomenon (called the *Independent* variable). Over time, mathematicians developed the convention of calling the independent variable x - and plotting it on the horizontal axis - and the dependent variable y - and plotting it on the vertical axis. As with all conventions, the purpose is simply to make it easier for everybody to read - no more and no less, but still important.



So if you wanted to examine how (as an example) people's ability to hear very high musical notes was related to their age, your assumption is that the ability is *dependent' on age. So your dependent variable is y, on the vertical axis, and the independent variable is x, on the horizontal axis.



Does that help? I hope so. It's only when people ask questions like that ('why have we always done it like this?) that they start to make interesting discoveries. Good luck and may you make excellent use of your curiosity.

Answer 3

If memory serves me correctly, time (if it's one of your variables) is normally the x-axis. Otherwise, if it's a plot of an experiment you have carried out, the variable you have altered is put on the the x-axis; the measured variable on the y.



I think that it's just convention, but you can pretty much plot what you like where you like. I guess it depends on the relationship you're looking at!

Answer 4

The independent variable is usually plotted on the horizontal (x) axis, while the dependent variable is plotted on the vertical (y) axis. This convention makes it possible to see how the dependent variable changes with changes in the independent variable.

Answer 5

it doesnt strictly matter what goes on which axis - it depend what you want to show tho.



take for example a distance - time graph. distance goes on the y axis and time on x axis because so that the gradient has the units m s^-1 ie speed.

if you plotted on opposite axis then the gradient would be in units of s m^-1 or the inverse of speed which obviously isnt as helpful.



so think of the relationship you wish to show before deciding on what goes on what axis.

Answer 6

The variable you change goes on your X axis, while the other one goes on the Y axis. e.g



f(g)=g^2.



g would go on the x axis since we can choose it to be anything

f would go on the y axis since it depends on g.

Answer 7

It is a convention and previous correspondents are correct about the dependent/independent variable situation but it is a convention that cannot be ignored in certain circumstances such as examination questions where knowing the convention may be part of the answer. Your teacher should be able to advise you about this if you are taking an examination.

Answer 8

Independent=x Dependent=y

Answer 9

Indepent (the one you set) on X-axis

Dependant on Y-axis