FX:SPX500   S&P 500 index of US listed shares
162 0 4
The standard deviations of the highs and lows are done separately. The result is Bollinger Band composite that works better for setting extreme points where the price will most likely not breach. The method for timing the entries are oscillators such as stochastics or Rsi .
These boundaries can then be used to set credit spreads such as call and put vertical spreads.

study(shorttitle="HL BB", title="High Low Bollinger Bands", overlay=true)
length = input(20, minval=1)
src             = input(low, title="Source")
src2 = input(high, title="Source2")
mult = input(3.0, minval=0.001, maxval=50)
mult2 = input(3.0, minval=0.001, maxval=50)
basis = sma ( src             , length)
basis2 = sma (src2, length)
dev = mult * stdev( src             , length)
dev2= mult2 * stdev(src2,length)
upper = basis2 + dev2
lower = basis - dev
plot(basis, color=orange)
plot(basis2,color=orange)
p1 = plot(upper, color=red)
p2 = plot(lower, color=blue)
fill(p1, p2)
United States
United Kingdom
India
Deutschland
España
France
Italia
Polska
Brasil
Россия
Türkiye
Indonesia
Malaysia
日本
한국
中国
Home Stock Screener Forex Signal Finder Economic Calendar How It Works Chart Features House Rules Moderators Website & Broker Solutions Widgets Stock Charting Library Priority Support Feature Request Blog & News FAQ Help & Wiki Twitter
Profile Profile Settings Account and Billing Priority Support Ideas Published Followers Following Private Messages Chat Sign Out