Linear Regression Slope

nio:=Input("Number of points taken to calculate the ROCs",3,1000,14);

rll:=ROC(O,nio-1,%)/(nio-1);
rl:=ROC(O,nio,%)/nio;
rh:=ROC(O,nio+1,%)/(nio+1);
rhh:=ROC(O,nio+2,%)/(nio+2);

xio:=Input("Distances of ROCs from interpolation point XIO ",0.01,1,0.5);

rit:=(rll / (1+xio) +
rl / (xio+.0001)+
rh / (1-xio) +
rhh / (2-xio)) /
( 1 / (1+xio) + 1 / (xio+.0001) + 1 / (1-xio) + 1 / (2-xio));

ro:=LinRegSlope(LinRegSlope(rit,nio),nio);
ro