$BTC Let’s assume we want to calculate the Bollinger Bands indicator for a specific company's stock using a 20-day time period:

Calculating the middle line (moving average)

| Day | Closing Price | Moving Average |

| ---------- | --------------------- | ----------------------------- |

| 1 | 100 | - |

| 2 | 105 | - |

| 3 | 110 | - |

| ... | ... | ... |

| 20 | 120 | 110 |

Calculating the standard deviation

| Day | Closing Price | Standard