Rolling z-score bars (top) = how many standard deviations price sits from its N-day average; green β€ β2Ο (oversold), red β₯ +2Ο (overbought). Below: price with its N-day moving average and Bollinger Β±2Ο band, and a dot on the latest close. Same timeline, so the z-score's extremes line up with the band touches.
How to read the price chart
- White line β the stock's actual closing price, day by day.
- Dashed line β the moving average (the average close over the selected window). It's the "center of gravity" the price wanders around.
- Blue band β the Bollinger Band: the moving average Β±2 standard deviations. Top edge = +2Ο (overbought), middle = the average, bottom edge = β2Ο (oversold).
The band is the z-score drawn in price terms. When the white line touches the bottom edge the stock is statistically oversold; riding the top edge means overbought. Read straight down from the bars above: a tall red bar lines up with a top-edge touch, a tall green bar with a bottom-edge touch.
Watch the band's width: a wide band means the stock has been volatile; a narrow "pinch" means a quiet, low-volatility stretch that often precedes a big move. Edges are not hard walls β in a strong trend price can "walk the band," so the trend direction (is the band sloping up or down?) matters as much as the touch itself.