2. Mean, Variance Standard Deviation (6 points) Your stock investments return 8%, 12%, and -4% in consecutive years. What is the mean return, X ? 21=1 Xi sum of all observations X N number of observations o What is the sample standard deviation, o? (hint: find variance o2 first) =(xi-x)2 sum of squared deviations from the mean N-1 number of observations - 1 02 = =