Given the following data sample, how confident can we be that the mean is greater than 40? 64 70 20 58 13 74 84 47 17 2. You are given the following sample of annual returns for portfolio manager: If you believe that the distribution of returns has been stable over time and will continue to be stable over time; how confident should you be that the portfolio manager will continue to produce positive returns? -7% 7% 19% 23 % -18 % -12% 49% 34% ~6% -20% 3 . You are presented with an investment strategy with a mean return of 20% and standard deviation of 10%_ What is the probability of a negative return if the returns are normally distributed? What if the distribution is symmetrical, but otherwise unknown?'