Chapter 25, Problem 6E

(a)

To determine

To explain which of these tests is appropriate for these data.

Answer to Problem 6E

Two-sample t -test is appropriate.

Explanation of Solution

In this question Simpson, Alsen and Eden report the results of trials in which clouds were seeded and the amount of rainfall were recorded. And the authors report on $26$ seeded and $26$ un-seeded clouds in order of the amount of rainfall, for which largest amount considered as first. And in question there are two possible tests to study the question of whether cloud seeding works. The software output is given as well. The tests conducted were: paired t -test and two-sample t -test. Thus, for this data the two-sample t -test is appropriate because the seeded and un-seeded clouds are not paired in any way/ are independent.

(b)

To determine

To state your conclusion using the test you have selected.

Explanation of Solution

In this question Simpson, Alsen and Eden report the results of trials in which clouds were seeded and the amount of rainfall were recorded. And the authors report on $26$ seeded and $26$ un-seeded clouds in order of the amount of rainfall, for which largest amount considered as first. And in question there are two possible tests to study the question of whether cloud seeding works. The software output is given as well. The tests conducted were: paired t -test and two-sample t -test. Thus, for this data the two-sample t -test is appropriate. So, we conclude that our p-value should come out as $0.0538$ . And this shows that the mean rainfall from seeded clouds is greater than the mean rainfall from un-seeded clouds.