Simpson, Alsen, and Eden (Technimetrics 1975) report the results of trials in which clouds were seeded and the amount of rainfall recorded. The authors report on 26 seeded and 26 unseeded clouds in order of the amount of rainfall, largest amount first Here are two possible tests to study the question of whether cloud seeding works.
Paired t-Test of ((1 - 2)
Mean of Paired Differences = -277.39615
t-Statistic = -3.641 with 25 df
p = 0.0012
2-Sample t-Test of (1 - (2
Difference Between Means = -277.4
t-Statistic = -1.998 with 33 df
p = 0.0538
a) Which of these tests is appropriate for these data? Explain.
b) Using the test you selected, state your conclusion.