A researcher is interested in the survival times of a particular organism after it is subjected to three substances. The first is a radioactive material, the second is a biological material, and the third is a chemical (nonradioactive) substance. Organisms are brought into contact with each of the three substances to see how long they will last (in hours) until they die. The times are recorded for each substance used in the study, and the results are given below:
$$\begin{array} { | l | l | }
\hline \text { Substance type } & \text { Lifetime } \
\hline \text { Radioactive } & 26,29,33 \
\hline \text { Biological } & 27,29,31 \
\hline \text { Chemical } & 31,34,37 \
\hline
\end{array}$$ What is the P-value of the Kruskal-Wallis statistic, H, for these data?

Question

A researcher is interested in the survival times of a particular organism after it is subjected to three substances. The first is a radioactive material, the second is a biological material, and the third is a chemical (nonradioactive) substance. Organisms are brought into contact with each of the three substances to see how long they will last (in hours) until they die. The times are recorded for each substance used in the study, and the results are given below:
$$\begin{array} { | l | l | } 
\hline \text { Substance type } & \text { Lifetime } \
\hline \text { Radioactive } & 26,29,33 \
\hline \text { Biological } & 27,29,31 \
\hline \text { Chemical } & 31,34,37 \
\hline
\end{array}$$ What is the P-value of the Kruskal-Wallis statistic, H, for these data?

Quizplus · Accepted Answer

The Kruskal-Wallis test is a non-parametric method used to determine if there are statistically significant differences between two or more groups of an independent variable on a continuous or ordinal dependent variable. It's an extension of the Mann-Whitney U test to more than two groups. The P-value indicates the probability of observing the data, or something more extreme, if the null hypothesis is true. Given the small sample sizes and the overlap in the lifetimes among the three groups, it's reasonable to expect that the differences among the groups might not be statistically significant, leading to a P-value greater than 0.10.

A Researcher Is Interested in the Survival Times of a Particular