Name the designs. What is the name for each of these study designs?

(a) A study to compare two methods of preserving wood started with boards of southern white pine.

Each board was ripped from end to end to form two edge-matched specimens. One was assigned

to Method A; the other, to Method B.

(b) A survey on youth and smoking contacted by telephone 300 smokers and 300 nonsmokers, all 14 to

22 years of age.

(c) Does air pollution induce DNA mutations in mice? Starting with 40 male and 40 female mice, 20 of

each sex were housed in a polluted industrial area downwind from a steel mill. The other 20 of

each sex were housed at an unpolluted rural location 30 kilometers away.