Question：In calculating the regression equation linking two variables, the standard formulae for the regression coefficients are given in terms of X and Y.
　　Which of the following is true?
　　A. Y must be the variable shown on the vertical axis of a scatter diagram
　　B. Y must be the dependent variable
　　C. It does not matter which variable is which
　　D. X must be the variable which will be forecast
　　The correct answer is: Y must be the dependent variable
　　The independent variable is denoted by X and the dependent one by Y.