I. The data used in this example were collected in southern Florida between 1968
ID: 3126500 • Letter: I
Question
I. The data used in this example were collected in southern Florida between 1968 and 1972 to determine whether injection of silver sodide into cumulus clouds (cloud seeding) tends to increase rainfall. Fifty-two days when weather conditions were suitable for cloud seeding were randomly divided into two groups of 26 days. For one group of 26 days the target cloud was injected with silver iodide (the target cloud was seeded). For the other group of 26 days the target cloud was not injected with silver iodide (the target cloud was not seeded). For each of the 52 days, the total amount of rainfall was mensured. The unit of measurement for the amount of ranfall is acre feet. (One acre foot of rain is the tends to increase rainfall. Fifty-two days when weather conditions were s volume needed to cover one acre to a depth of one foot.) Cloud seeding data (rainfall amounts in acre-feet) seeded days 4.1 7.7 17.5 31.4 32.7 40.6 92.4 115.3 118.3 119.0 129.6 198.6 200.7 242.5 255.0 274.7 274.7 302.8 334.1 430.0 489.1 703.4 978.0 1656.0 1697.8 2745.6 unseeded days 1.0 4.9 4.9 11.5 17.3 21.7 24.426.1 26.3 28.6 29.0 36.6 411 47.3 68.5 81.2 87.0 95.0 147.8 163.0 244.3 321.2 345.5 372.4 830.1 1202.6 Summary statistics seeded unseeded min4.1 01 92.4 med 221.6 3 430.0 max 2745.6 range 2742 IQR 337.6 min 1.0 01 24.4 med 44.2 Q3 163.0 max 1202.6 range 1202 IQR 138.6 mean 441.98 std. dev. 650.79 mean 164.59 std dev. 278.43Explanation / Answer
In (C) and (D) we have already discussed that the loaction and spread parameter of the distribution of the rainfall in the seeded days are significantly higher than that of unseeded days. We will now notice that the minimum and maximum amount of the rainfall in the seeded days is also higher than that of unseeded days. Also the Median values. But these calculations are also eye-seeing. If you want to observe the effect of cloud seeding on the rainfall amount then you can do a ANOVA test. Just put the data in Excel and do a one way anova test. Then you can see that the effect of cloud seeding has a significant effect on the amount of rainfall. So We can conclude that the cloud seeding offers a very tangible effect on the rainfall.