It is measured on an interval scale in pounds. Height is an independent variable. It is measured on an interval scale in inches. Age is an independent variable. It is measured on an interval scale in years.
Sex is an independent variable.
We can begin with a bivariate analysis, with weight as the dependent variable and height as the independent variable. We can see this graphically by using the Scatterplot procedure. To predict someone's weight we take their height, multiply it by 6.596, and subtract 291.542. If we use the Regression procedure, the diagram looks like this. Sum of Squares DF Mean Square F Prob.