se the price data from the table that follows for the Standard & Poors 500 Index, Wal-mart, and Target to calculate the holding-period returns for the 24 months from July 2010 through June 2012.

Month	S&P 500	Wal-mart	Target
June-10	$1,030.71	$48.07	$49.17
Jul-10	1,101.60	51.19	51.32
Aug-10	1,049.33	50.14	51.16
Sep-10	1,141.20	53.52	53.44
Oct-10	1,183.26	54.17	51.94
Nov-10	1,180.55	54.09	56.94
Dec-10	1,257.64	53.93	60.13
Jan-11	1,286.12	56.07	54.83
Feb-11	1,327.22	51.98	52.55
Mar-11	1,325.83	52.05	50.01
Apr-11	1,363.61	54.98	49.10
May-11	1,345.20	55.22	49.53
Jun-11	1,320.64	53.14	46.91
Jul-11	1,292.28	52.71	51.49
Aug-11	1,218.89	53.19	51.67
Sep-11	1,131.42	51.90	49.04
Oct-11	1,253.30	56.72	54.75
Nov-11	1,246.96	58.90	52.70
Dec-11	1,257.60	59.76	51.22
Jan-12	1,312.41	61.36	50.81
Feb-12	1,365.68	59.08	56.69
Mar-12	1,408.47	61.20	58.27
Apr-12	1,397.91	58.91	57.94
May-12	1,310.33	65.82	57.91
Jun-12	1,355.69	67.70	57.40

Now assuming that you have decided to invest equal amounts of money in Wal-mart, Target, and long-term government securities, calculate the monthly returns for your three-asset portfolio. What is the average return and the standard deviation?