please show work , for the first one im specifically confused on how to solve for the standard deviation and what would be the "n" in the standard deviation formula

2) The graph shows that the monthly return on Tardis Intertemporal (TI) is expected to fall between -0.412% and 2 642%. The expected return on Tardis Intertemporal (TU) is Normal Distribution and the standard deviation is 3) XYZ stock declares a 50.64/share dividend on January 8, payable on February 17 to holders of record January 29. If you buy 700 shares of XYZ on January 31 at $52.18/share and sell it on February 4 at 551 25/share, you will earn total dividends of and total returns of