Note: Your answers to the questions below should follow the expectations for homework found here (and demonstrated here). Date due on Dates page.

Commitment to Adult Animals

Commitment to Animals

A researcher has constructed a “survey” to determine an individual person’s “commitment to adult animals.” Each individual survey leads to a single number that measures that individual’s “commitment.” This number is larger for “greater commitments.” The researcher wanted to determine if the mean “commitment” according to this measure was greater for people who evacuated all or some of their pets versus those who did not evacuate any pets during a propane tanker derailment in Weyauwega, Wisconsin in 1996. The table below shows the results for the “commitment” measure for 116 individuals that evacuated all or some of their pets (i.e., DidEvac) and for 125 individuals that evacuated none of their pets (i.e., NoEvac). Also note that the Levene’s p-value for these data is 0.678. Use these results to examine the researcher’s hypothesis at the 1% significance level.

Variable   n  Mean Median StDev SE Mean   Min    Max    Q1    Q3
DidEvac  116 7.694  7.658 3.410  0.317  -0.863 14.763 5.035 10.204
NoEvac   125 6.640  6.599 3.102  0.277  -1.214 14.444 4.568  8.696

Methyl Mercury in Mussels

Freshwater Mussel

Mierzykowski and Carr (2001) examined the amount of methyl-mercury in freshwater mussels (Elliptio complanata) in four areas in the Sudbury River watershed in Massachusetts. Two of the locations they examined were categorized as reservoirs with one being considered as impacted by the Nyanza Chemical site and the other as not being impacted. The total methyl mercury (in μg meHG per g wet-weight of mussels) for individual mussels sampled from each site is shown below. Use these data to determine if there is a significant difference, at the 5% level, in methyl mercury levels found in mussels between the two locations. Continue with the analysis even if you find that the assumptions have not been met.

impacted  0.011 0.054 0.056 0.095 0.051 0.077
reference 0.031 0.040 0.029 0.066 0.018 0.042 0.044