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<br />Table 2.1. - Estimation of the number of cases (N) that will be required for the cold cloud seeding <br />demonstration project to reach a statistical significance level of 0.05 at a power of 0.80 as a function <br />of possible seeding effect. Top: for individual cells. Bottom: for experimental units. <br /> <br />RVOL for individual cells <br />(ex = 0.05 and 1 - j3 = 0.80) <br />Var(SR) = 21.0 and SE(SR) = 1.22 <br /> <br />DELTA <br />N <br /> <br />0.5 <br />659 <br /> <br />1.0 <br />165 <br /> <br />1.5 <br />73 <br /> <br />2.0 <br />32 <br /> <br />2.5 <br />21 <br /> <br />Note: A total of 151 cells have been obtained from 14 random cases in Thailand to date with 8 = 0.€,9. <br />The sample of cells, obtained from 10 random cases having cloud bases> 16 oC, is 108. The estimated <br />8 for that sample is 1.25. <br /> <br />RVOL for random cases for 150 minutes after initial treatment <br />(ex = 0.05 and 1 - j3 = 0.80) . <br />Var(SR) = 13.5 and SE(SR) = 0.94 <br /> <br />DELTA <br />N <br /> <br />0.3 <br />927 <br /> <br />0.4 <br />522 <br /> <br />0.5 <br />334 <br /> <br />0.6 <br />148 <br /> <br />0.7 <br />109 <br /> <br />Note: The above estimates of N are based on only 14 random cases and may, therefore, not be <br />representative. The current 8 of 0.66 is not yet a strong indication for the real magnitude of the effect <br />in view of the high Var(SR). <br /> <br />Table 2.2. - Estimation of the number of cases (N) that will be required in Texas to reach a statistical <br />significance level of 0.05 at a power of 0.80 as a function of possible seeding effect. Top: for individual <br />cells. Bottom: for experimental units. <br /> <br />RVOL for individual cells <br />(ex = 0.05 and 1 - /3 = 0.80) <br />Var(SR) = 7.25 and SE(SR) = 1.22 <br /> <br />DELTA <br />N <br /> <br />0.5 <br />179 <br /> <br />1.0 <br />45 <br /> <br />1.5 <br />20 <br /> <br />2.0 <br />11 <br /> <br />2.5 <br />7 <br /> <br />Note: A total of 183 cells have been obtained from 24 random cases in Texas to date with 8 = 1.30. <br />The sample of cells, obtained from 10 random cases having cloud bases> 16 oC, is 85, and the 8 for <br />that sample is 1.85. <br /> <br />.1 <br />, 1 <br /> <br />RVOL for random cases for 150 minutes after initial treatment <br />(ex = 0.05 and 1 - j3 = 0.80) <br />Var(SR) = 5.50 and SE(SR) = 0.40 <br /> <br />DELTA <br />N <br /> <br />0.1 <br />3400 <br /> <br />0.2 <br />850 <br /> <br />0.3 <br />378 <br /> <br />0.4 <br />213 <br /> <br />0.5 <br />136 <br /> <br />Note: The above estimates of N are based on a random sample of 34 random cases and may, therefore, <br />not yet be representative. The current 8 is 0.27. <br /> <br />16 <br />