+The @subcmd{ORIGIN} and @subcmd{NOORIGIN} subcommands are mutually
+exclusive. @subcmd{ORIGIN} indicates that the regression should be
+performed through the origin. You should use this option if, and
+only if you have reason to believe that the regression does indeed
+pass through the origin --- that is to say, the value @math{b_0} above,
+is zero. The default is @subcmd{NOORIGIN}.
+