Consider the following table of daily closing prices of a particular stock.

Day: 0 1 2 3 4 5 6 7 8 9 10 11 12

Close: 53.3 51.8 51.9 55.5 54.5 54.1 56.0 60.0 59.5 58.4 60.2 57.4 58.7

(a) Assuming that stock price follows a G.B.M., use the closing data to estimate the (per annum) volatility .

(b) No help given. If the data were monthly, rather than daily, what would be your answer to (a)? Give the intuition as well as the calculation.

please show method