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Project Storm Fury. Review. A stochastic variable has the following probability distribution:. Review. What is X’s cumulative probability distribution? What is its expected value ( X =?) What is the Variance of X? What is its standard deviation?. Review. What is the Variance of X?
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Review A stochastic variable has the following probability distribution:
Review • What is X’s cumulative probability distribution? • What is its expected value (X=?) • What is the Variance of X? • What is its standard deviation?
Review What is the Variance of X? VarX = xi2P(X=xi) - 2 = [1(1/3) + 22(1/3) + 32(1/3)] - 22 = (1/3 + 4/3 + 3) - 4 = 2/3 What is its standard deviation ()? X = SqrRoot(VarX) = (2/3)1/2 = .8165
Alternative Hypotheses • H1, the “beneficial” hypothesis. The average effect of seeding is to reduce maximum sustained wind speed. • H2, the “null” hypothesis. Seeding has no effect on hurricanes. No change is induced in maximum sustained wind speed. • H3, the “detrimental” hypothesis. The average effect of seeding is to increase the maximum sustained wind speed.
Mathematical expressions • P(w' | H2) = P(w) = fN(100%, 15.6%) • P(w' | H1) = ƒN(85, 18.6%) • P(w' | H3 ) = ƒN(110%, 18.6%)
Probability density function for Debbie results • P(69, 85 | H1) = 1.50 x 2.14 =3.21 • P(69, 85 | H2) = 0.372 x 1.64 = 0.61 • P(69, 85 | H3) = 0.195 X 0.886 = 0.173 P(H1 | 69, 85) = (3.21 x 1/3)/(3.21 x 1/3 + 0.61 x 1/3 + 0.173 x 1/3) = .81 P(H2 | 69, 85) = .15 P(H3 | 69, 85) = .04
P(H1) = .15 P(H2) = .75 P(H3) = .10 P(H1) = .49 P(H2) = .49 P(H3) = .02 Prior probabilities - pre and post Debbie .81(.15)/ [.81(.15) +.15(.75) + .04(.1)] = .51 .15(.75)/ [.81(.15) +.15(.75) + .04(.1)] = .47 .04(.1)/ [.81(.15) +.15(.75) + .04(.1)] = .02
Probabilities assigned to wind changes occurring in the 12 hours before hurricane landfall Cumulative probability functions
Probabilities assigned to wind changes occurring in the 12 hours before hurricane landfall. Discrete approximation for five outcomes.
Review • Decide whose benefits and costs count, and how much. This is typically referred to as determining standing. • Select the portfolio of alternative initiatives. • Catalog potential consequences and select measurement indicators. • Predict quantitative consequences over the life of the project for those who have standing. • Monetize (attach cash values to) all the predicted consequences. • Discount for time to find present values. • Sum up benefits and Costs for each initiative and Perform sensitivity analysis underlying key assumptions
Adapting to Climate Change 5 Source: Oregon Environmental Quality Commission, Oregon Climate Change Adaptation Framework. December 10, 2010, Salem OR