Eccolo:

//PRC_Std and Ste LinRegChannel | indicator
//Standard Deviation and Standard Error
//Linear Regression Channel
//12.03.2019
//Nicolas @ www.prorealcode.com
//Sharing ProRealTime knowledge
//
//defparam drawonlastbaronly=true
//defparam calculateonlastbars=1000
// --- settings
lookback= 200 //channel period
ChannelType = 1 //1= Standard Deviation ; 2= Standard Erro
NbDeviation = 1 //Deviation multiplier
//colorRed = 255
//colorGreen = 255
//colorBlue = 0
// --- end of settings

sumx = 0
sumy = 0
sumxy = 0
sumx2 = 0

for cmpt = lookback downto 0 do
tmpx = cmpt
tmpy = close[cmpt]
sumy = sumy+tmpy
sumx = sumx+tmpx
sumx2 = sumx2 + (tmpx*tmpx)
sumxy = sumxy + (tmpy*tmpx)
next

n = lookback+1

if (sumx2 = sumx * sumx) then // protection to avoid infinite values
b = sumxy - sumx * sumy
else
b = (n * sumxy - sumx * sumy) / (n * sumx2 - sumx * sumx)
endif
a = (sumy - b * sumx) / n

//drawsegment(barindex[lookback],a+b*lookback,barindex,a+b*0) coloured(colorRed,colorGreen,colorBlue)

//channel
if ChannelType = 1 then //Standard Deviation
dat = std[lookback]*NbDeviation
else
dat = ste[lookback]*NbDeviation
endif
//drawsegment(barindex[lookback],(a+b*lookback)+dat,barindex,a+b*0+dat) coloured(colorRed,colorGreen,colorBlue)
//drawsegment(barindex[lookback],(a+b*lookback)-dat,barindex,a+b*0-dat) coloured(colorRed,colorGreen,colorBlue)

UPPERline1  = (a+dat) * 1.05      //+5%
UPPERline2  = (a+dat) * 0.95      //-5%
LOWERline1  = (a-dat) * 1.05      //+5%
LOWERline2  = (a-dat) * 0.95      //-5%

Cond = 0
IF close >= UPPERline2 AND close <= UPPERline1 THEN
Cond = 1
ELSIF close >= LOWERline2 AND close <= LOWERline1 THEN
Cond = 2
ENDIF

SCREENER[Cond](Cond AS "1=↑,2=↓")