Contents
- abs
- add
- all_time_high
- all_time_low
- and
- approx
- aroon_down
- aroon_osc
- aroon_up
- atr
- bb_lower
- bb_upper
- bb_width
- cci
- change
- cond
- count
- cross
- crossover
- crossunder
- cumsum
- days_since
- dev
- deviation
- div
- ema
- eq
- falling
- floordiv
- gain
- gt
- gte
- highest
- highest_bars_ago
- hma
- kc_lower
- kc_middle
- kc_upper
- kcw
- loss
- lowest
- lowest_bars_ago
- lt
- lte
- macd_histogram
- macd_line
- macd_signal
- max
- mean
- median
- mfi
- min
- mod
- mom
- months_since
- mul
- ne
- obv
- offset
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- pct_change
- percentrank
- pivothigh
- pivotlow
- pow
- range
- rising
- roc
- rsi
- sma
- sqrt
- stdev
- stoch_d
- stoch_k
- streak
- sub
- sum
- swma
- true_range
- universe_percentile
- variance
- vwma
- weeks_since
- wilderma
- williams_r
- wma
- years_since
No matches
bb_lower
Bollinger Bands Lower Band (MA - num_stdev * stdev)
bb_lower(source, period, num_stdev, matype="sma")
Parameters
| Name | Type | Description |
|---|---|---|
source |
field | Data series (typically close) |
period |
int | MA and stdev period |
num_stdev |
float | Number of standard deviations |
Formula
BB Lower = MA(source, period) - num_stdev * stdev(source, period)Examples
close < bb_lower(close, 20, 2); // Price breakdown below lower band/* price pierced below lower band (2.5 deviations), but closed above */
low < bb_lower(close, 20, 2.5) and close > bb_lower(close, 20, 2.5);/* lower bollinger band falling (expanding volatility) for 3 consecutive bars */
falling(bb_lower(close, 20, 2.0), 3) == true;/* lower bollinger band rising (contracting volatility) for 3 consecutive bars */
rising(bb_lower(close, 20, 2.0), 3) == true;Returns
float
Range
period is bound by matype's MA family (2-210 ema, 2-105 wilder) or the 2-400 windowed range for the default sma/wma, whichever is tighter, since the same period also sizes stdev()
Notes
Prices touching/exceeding the lower band may indicate oversold; wider bands (higher num_stdev) are more conservative signals