Suppose we want to compare the output of strawberries grown on plots using fertilizer A with that grown on otherwise identical plots using fertilizer B in order to make a general assessment of relative fertilizer effectiveness. Which of the following tests might we use?
A) a Friedman-Smirnov test
B) a Kruskal-Wallis test
C) a Wilcoxon rank sum test
D) a Spearman rank correlation test

Question

Quizplus · Accepted Answer

The Wilcoxon rank sum test is appropriate for comparing two independent samples, which is what we have in this scenario (strawberries grown with fertilizer A vs. strawberries grown with fertilizer B). The Friedman-Smirnov test and Kruskal-Wallis test are appropriate for comparing multiple groups, so they are not the best choice in this scenario. The Spearman rank correlation test is used to assess the strength and direction of a relationship between two variables, but we are not interested in a correlation in this scenario, so it is also not the best choice.

Suppose We Want to Compare the Output of Strawberries Grown