The basic calculation for volatility (denoted ) as used in option pricing is the annualized standard deviation

The basic calculation for volatility (denoted σ) as used in option pricing is the annualized standard deviation of continuously compounded daily returns. Calculate volatility for Dollar General Corporation (NYSE: DG) based on its closing prices for two weeks, given in the table below. (Annualize based on 250 days in a year.)
Dollar General Corporation Daily Closing Stock Price
Date....................................... Closing Price ($)
27 January 2003.......................... 10.68
28 January 2003.......................... 10.87
29 January 2003.......................... 11.00
30 January 2003.......................... 10.95
31 January 2003.......................... 11.26
3 February 2003.......................... 11.31
4 February 2003.......................... 11.23
5 February 2003.......................... 10.91
6 February 2003.......................... 10.80
7 February 2003.......................... 10.47