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Comparing mosquito repellents. Which insect
Chapter 12, Problem 79E(choose chapter or problem)
Problem 79E
Comparing mosquito repellents. Which insect repellentsprotect best against mosquitoes? Consumer Reports (June2000) tested 14 products that all claim to be an effectivemosquito repellent. Each product was classified as eitherlotion/cream or aerosol/spray. The cost of the product (indollars) was divided by the amount of the repellent neededto cover exposed areas of the skin (about 1/3 ounce) toobtain a cost-per-use value. Effectiveness was measured asthe maximum number of hours of protection (in half-hour increments) provided when human testers exposed theirarms to 200 mosquitoes. The data from the report are listedin the table.
a. Suppose you want to use repellent type to modelthe cost per use (y). Create the appropriate numberof dummy variables for repellent type and write themodel.
b. Fit the model, part a, to the data.
c. Give the null hypothesis for testing whether repellenttype is a useful predictor of cost per use (y).
d. Conduct the test, part c, and give the appropriate conclusion. Use α = .10.
e. Repeat parts a–d if the dependent variable is the maximum number of hours of protection (y).
Questions & Answers
QUESTION:
Problem 79E
Comparing mosquito repellents. Which insect repellentsprotect best against mosquitoes? Consumer Reports (June2000) tested 14 products that all claim to be an effectivemosquito repellent. Each product was classified as eitherlotion/cream or aerosol/spray. The cost of the product (indollars) was divided by the amount of the repellent neededto cover exposed areas of the skin (about 1/3 ounce) toobtain a cost-per-use value. Effectiveness was measured asthe maximum number of hours of protection (in half-hour increments) provided when human testers exposed theirarms to 200 mosquitoes. The data from the report are listedin the table.
a. Suppose you want to use repellent type to modelthe cost per use (y). Create the appropriate numberof dummy variables for repellent type and write themodel.
b. Fit the model, part a, to the data.
c. Give the null hypothesis for testing whether repellenttype is a useful predictor of cost per use (y).
d. Conduct the test, part c, and give the appropriate conclusion. Use α = .10.
e. Repeat parts a–d if the dependent variable is the maximum number of hours of protection (y).
ANSWER:Step 1 of 7
a) Suppose we want to use repellent type to model the cost per use (y).
From the given information the appropriate model for repellent type to model the
cost per use:
