For the following questions identify the response variable(s), explanatory variable(s) and classify each variable as quantitative or categorical. If categorical indicate whether or not it is binary. Finally, identify the appropriate model/test (test of proportions (p tests, chi-square), test of means (t-test, ANOVA), (simple or multiple) linear regression). If no test is valid or appropriate explain why.

1.) Are child poverty rates in Iowa associated with the size of county? A stratified random sample of 12 counties in Iowa (stratified by size of county - small, medium, or large) includes information about the child poverty rates in the counties.

2.) How does an acidic environment and the distance from the main source of daylight affect the growth of alfalfa plants? Students planted alfalfa seeds in 15 cups. They gave 5 plants plain water, 5 plants a moderate amount of acid (1.5M HCL), and 5 a stronger amount of acid solution (3.0M HCL). Further, the plants were arranged into 5 rows of 3, with row a = farthest from the source of light through e = nearest to the source of light.

3.) Does the weight of a sparrow help predict wing length? Priscilla Erickson from Kenyon College collected data on a stratified random sample of 116 Savannah sparrows at Kent Island. The weight (in grams) and wing length (in mm) were obtained for birds from nests that were reduced, controlled, or enlarged.

4.) Does the rate of infection change at a hospital based on the institution of handwashing procedures? Ignaz Semmelweiss (1818-1865) was the doctor who first encouraged other doctors to wash their hands with disinfectant before touching patients. Before the new procedure was established, the rate of infection at Dr. Semmelweiss's hospital was about 10% and afterwards dropped to about 1%.