Chapters: 1: Introduction 2: Simple example 3: Invocation 4: Finer Control 5: X-Y Plots 6: Contour Plots 7: Image Plots 8: Examples 9: Gri Commands 10: Programming 11: Environment 12: Emacs Mode 13: History 14: Installation 15: Gri Bugs 16: Test Suite 17: Gri in Press 18: Acknowledgments 19: License Indices: Concepts Commands Variables | ### 9.3.34: ``regress`'
    `regress {y vs x [linear]}|{x vs y [linear]}'
Perform linear regression of ``y`' as a function of ``x`' or ``x`' as a function of ``y`'. ``regress y vs x`' Linear regression of y vs x. Several quantities are reported and also saved into builtin variables. The intercept is defined as ``..coeff0..`', its 95 percent confidence limit is defined as ``..coeff0_sig..`'. Thus the confidence range is ``..coeff0..-..coeff0_sig..`' to ``..coeff0..+..coeff0_sig..`'. Similarly the slope and confidence limit are stored in ``..coeff1..`' and ``..coeff1_sig..`' The squared correlation coefficient is stored in ``..R2..`'. Historical note prior to version 2.1.15, a different meaning was attached to ``..coeff0_sig..`' and ``..coeff1_sig..`'; they used be defined as standard errors, without having been multiplied by the appropriate student-t coefficient. ``regress x vs y`' Linear regression of x vs y; for notation see above. ``regress y vs x linear`' Linear regression of y vs x; for notation see above. ``regress x vs y linear`' Linear regression of x vs y; for notation see above.