What makes two variables dependent?

Answer 1

There is the mathematical use and statistical use of the word "dependent" as explained on the related link. The mathematical use is a dependent variable is the outcome of a function with one or more independent variables. The statistical definition in the setting of an experiment, is similar, it is a variable which is expected to be affected by changes in independent variables. Example: If I don't eat (quantity of food- independent variable), I will be hungry (dependent variable). I will not have as much energy (second dependent variable). But nothing is perfect in experimentation. The circumstances of the experiment with numerous unknown relationships may cause unexpected results. In observational studes, with typically less control, variables can be hypothesized (or conjectured) to be related, i.e. global warming causes artic ice to melt, and artic ice melting leads to more global warming. This would also be called a feedback effect. I can produce a dependent series of numbers from an independent series. If I take a series of random numbers of size N which come from a given distribution, and rank them from low to high , with n = 1 for the lowest and n = N for the highest, the ranks become dependent variables. A change in one value could affect the rank of another variable. I have included some more information on dependent variables. See related links.