13. Contaminants in Chemicals A manufacturer uses two suppliers of a certain chemical and wants to test whether the percentage of contaminants is the same for the two sources.

Data from independent random samples are shown below:

a. Use the Wilcoxon rank sum test to determine whether there is a difference in the contaminant percentages for the two suppliers. Use a 5.05.

b. Use the large-sample approximation to the Wilcoxon rank sum test to determine whether there is a difference in the contaminant percentages for the two suppliers.
Use a 5.05. Compare your conclusions to the conclusions from part a.

Transcribed Image Text:

Supplier 1 2 .86 .65 .55 .58 .69 1.13 .40 .16 .72 .65 .22 .07 1.18 .50 .09 .36 .45 1.04 .16 .20 1.41 .41 .26 .15