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Statistics · Ch 3 — Linear Regression

Prediction Using Regression Equations

5

Prediction Using Regression Equations

Once the regression equation is known, prediction is simple substitution:

  • To estimate YY for a given X=x0X = x_0, substitute x0x_0 into the regression equation of YY on XX.
  • To estimate XX for a given Y=y0Y = y_0, substitute y0y_0 into the regression equation of XX on YY.
Note

Never use the wrong line for prediction — using the XX-on-YY line to estimate YY from XX (or vice versa) gives a mathematically different, incorrect answer, since the two lines are derived by minimizing errors in different directions. …