Median real estate property taxes paid for housing units with mortgages in 2013: $590 (1.2%). Median real estate property taxes paid for housing units with no mortgage in 2013: $637 (1.5%). Nearest city with pop. 50,000+: Bismarck, ND (78.6 miles, pop. 55,532). Nearest city with pop. 200,000+: Minneapolis, MN (305.7 miles, pop. 382,618).
The third type of variable is a controlled variable. This variable is constant in an experiment. Experiments are repeated a number of times to interpret how a change in the independent variable affects each trial result.
Once a graph is constructed, it will be clear how much, and if, the independent variable influences the other. Not all equations and graphs are two-dimensional. In an experiment with two independent variables, which are usually designated as x and y, the dependent variable is usually z. The z-axis is the third dimension that typically represents depth or height.