The following spreadsheet contains monthly returns for cola co. and gas co. for 2013. using these data, estimate the average monthly return and the volatility for each stock. month cola co. gas co. january negative 9.90% 4.40% february negative 1.60% 5.60% march 4.20% negative 1.30% april negative 2.60% negative 2.00% may negative 9.10% negative 1.60% june negative 8.20% negative 3.80% july 12.00% 4.70% august negative 0.70% 0.40% september negative 7.00% negative 0.90% october 1.20% 0.40% november 9.20% 10.20% december negative 1.10% 5.50%