Note: Although not absolutely necessary, you are advised to use a computer spread- sheet to work the following problem. a. Use 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 May 2013 through May 2015.

MONTH	S&P 500	WAL-MART	TARGET
2013
May	$1,631	$74.84	$69.50
June	1,606	74.49	68.86
July	1,686	77.94	71.25
August	1,633	72.98	63.31
September	1,682	73.96	63.98
October	1,757	76.75	64.79
November	1,806	81.01	63.93
December	1,848	78.69	63.27
2014
January	1,783	74.68	56.64
February	1,859	74.7	62.54
March	1,872	76.43	60.51
April	1,884	79.71	61.75
May	1,924	76.77	56.76
June	1,960	75.07	57.95
July	1,931	73.58	59.59
August	2,003	75.5	60.07
September	1,972	76.47	62.68
October	2,018	76.27	61.82
November	2,068	87.54	74
December	2,059	85.88	75.91
2015
January	1,995	84.98	73.61
February	2,105	83.93	76.83
March	2,068	82.25	82.07
April	2,086	78.05	78.83
May	2,128	75.86	79.29

b. Calculate the average monthly holding-period returns and the standard deviation of these returns for the S&P 500 Index, Wal-Mart, and Target.