hi, say we have two variables.

engine size and rural driving fuel usage
and
engine size and urban driving fuel usage.

now these two variables are obviously linked no doubt.. however are they casual?

i did a scatter plot and it seemed that the relationship between engine size and rural driving fuel usage was greater than urban driving fuel usage.

what is the meaning behind this?

Read these: Correlation does not imply causation - Wikipedia, the free encyclopedia

Does Correlation Prove Causation | Reference.com

Tainted Ideals: Fallacy Friday: correlation and causation; a good working synopsis

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hey cheers for that.
so is this a fair statement?

- to say engine size and the fuel usage rate for either urban and rural driving is casual is incorrect as although they may be strongly correlated other factors are also responsible for the cause of the fuel usage rate increase or decrease.

Looks OK. Read these: Lurking Variables

Confounding - Wikipedia, the free encyclopedia

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