Royalties received by an investor in an oil well vary according to the price of the oil. Data collected were used to develop probability-royalty relationship: Calculate the expected value of the royalty income per year. Calculate the standard deviation of the royalty income. Determine the probability that the royalty income will be at least $ 12,000 per year. What is the best estimate of the percentage of royalty that will fall within 1 standard deviation of the mean