N:=20;
MD:SMA(CLOSE,N,1);
MID:=MA(C,N);
VART1:=POW((C-MD),2);
VART2:=MA(VART1,N);
VART3:=SQRT(VART2);
UPPER:=MD+2*VART3;
LOWER:=MD-2*VART3;
BOLL:=REF(MD,1),COLORFFFFFF;
UB:REF(UPPER,1),COLOR00FFFF;
LB:REF(LOWER,1),COLORFF00FF;
收口差率%:(UB/LB-1)*100,NODRAW,COLORWHITE;
