12. The cable below gives data on the monthly returns on the S&P 500 and small-cap stocks for the period January 1960 through December 1999 and provides statistics relating to their mean differences. Differences S&P 500 Small-Cap (S&P 500- Measure Return (9%) Stock Return (9%) Small-Cap Stock) January 1960-December 1999, 480 months Mean 1.0542 1.3117 -0.258 Standard deviation 4.2185 5.9570 3.752 January 1960-December 1979, 240 months Mean 0.6345 1.2741 -0.640 Standard deviation 4.0807 6.5829 4.096 January 1980-December 1999, 240 months Mean 1.4739 1.3492 0.125 Standard deviation 4.3197 5.2709 3.339