John has a utility function expressed by U(W)=W, where W stands for wealth (assuming wealth is positive, i.e. W>0), and U(W) is the utility given a certain level of W. John has initial wealth of $10,000. John feels that he faces the following probability distributions of losses with respect to his wealth: Probability 80% Loss Amount $0 $1,000 $9,000 10% 10% What is John's standard deviation of loss