Absolute & Relative Volume Change

study(title="absolute & relative volume change", shorttitle="ARVC")

//absolute volume change

x = input(5, minval=1)
y = sum(volume, x+1)-volume
z =x * volume / y 
Aupper = input(2.00, minval=0.01)
Alower = input(0.5, minval=0.01)

//relative volume change 
t = change (volume)
length = input(20, minval=1), mult = input(2.0, minval=0.001, maxval=50)
basis = sma(t, length)
dev = mult * stdev(t, length)
Rupper = basis + dev
Rlower = basis - dev

barcolor((z>Aupper and (t>Rupper or t<Rlower))? fuchsia : na)
barcolor((z<Alower and (t>Rlower or t<Rlower))? yellow : na)