Refer to the MegaStat/Excel Output for the Wilcoxon Rank Sum

question 43

Multiple Choice

Refer to the MegaStat/Excel output for the Wilcoxon rank sum test given in the table below. At a significance level of .05, which one of the following rejection point conditions is correct regarding the null hypothesis, H₀: D₁ and D₂ are identical probability distributions, and the alternative hypothesis of H_a: D₁ is shifted to the left of D₂.

• A) We reject H₀ and conclude that there is very strong evidence that the median value of the first sample significantly differs from the median value of the second sample.
• B) We reject H₀ and conclude that there is very strong evidence that the median value of the first sample is significantly less than the median value of the second sample.
• C) We do not reject H₀ and conclude there is not sufficient evidence that the median value of the first sample is significantly less than the median value of the second sample.
• D) We do not reject H₀ and conclude there is not sufficient evidence to conclude that the median value of the first sample is not significantly different than the median value of the second sample.
• E) We do not reject H₀ and conclude there is very strong evidence that the median value of the first sample is significantly less than the median value of the second sample.

---

Definitions:

Denitrification

Conversion of nitrates or nitrites to nitrogen gas.

Nitrogen Fixation

The process by which certain microorganisms convert atmospheric nitrogen into a form that can be used by plants to synthesize proteins and nucleic acids.

Ammonification

Ammonium-producing process of decomposition.

Nitrification

Conversion of ammonium to nitrate.