The nine-banded armadillo, Dasypus novemcinctus, is the only mammal other than humans known to suffer naturally from leprosy. This mammal is also unique in that pregnant females normally give birth to identical quadruplets. Medical scientists have found D. novemcinctus to be invaluable in the study of curative agents for this disease. Suppose that a scientist has developed a drug (LeproX) that she hopes will cure leprosy in humans. She needs to test the drug first on the nine-banded armadillo to determine the effectiveness and the potential for any deleterious side effects. She exposes sixteen offspring from four litters of armadillos to the disease pathogen. When all sixteen are showing early symptoms of the leprosy, the scientist randomly divides the sixteen into two groups of eight. Each group contains two sets of four identical quadruplets. One group of eight individuals (experiment group) is treated by intramuscular (IM) injection with 0.5 mg LeproX in a saline carrier per kg body weight three times a day for three weeks. The other group of eight individuals (control group) are treated with a saline placebo injection on the same schedule. At the end of the treatment phase, the sixteen armadillos are returned to a common holding pen where they live under identical conditions for the next two months. At the end of the second month, all individuals are examined for evidence and extent of the disease. Five members of the experimental group are symptom-free, two members show moderate progression of leprosy, and one member of the group is in an advanced state of the disease. Three members of the control group show moderate progression of the disease and five members of the group are in an advanced stage of leprosy. Questions State a reasonable hypothesis for the above Identify the independent variable of the Explain why you selected your answer. Identify the dependent variable of the Explain why you selected your answer. Identify 3 different control variables of this What was the treatment level used in this experiment?

Question

Armadillos and Leprosy

The nine-banded armadillo, Dasypus novemcinctus, is the only mammal other than humans known to suffer naturally from leprosy. This mammal is also unique in that pregnant females normally give birth to identical quadruplets. Medical scientists have found D. novemcinctus to be invaluable in the study of curative agents for this disease.

Suppose that a scientist has developed a drug (LeproX) that she hopes will cure leprosy in humans. She needs to test the drug first on the nine-banded armadillo to determine the effectiveness and the potential for any deleterious side effects. She exposes sixteen offspring from four litters of armadillos to the disease pathogen. When all sixteen are showing early symptoms of the leprosy, the scientist randomly divides the sixteen into two groups of eight. Each group contains two sets of four identical quadruplets.

One group of eight individuals (experiment group) is treated by intramuscular (IM) injection with 0.5 mg LeproX in a saline carrier per kg body weight three times a day for three weeks. The other group of eight individuals (control group) are treated with a saline placebo injection on the same schedule. At the end of the treatment phase, the sixteen armadillos are returned to a common holding pen where they live under identical conditions for the next two months.

At the end of the second month, all individuals are examined for evidence and extent of the disease. Five members of the experimental group are symptom-free, two members show moderate progression of leprosy, and one member of the group is in an advanced state of the disease. Three members of the control group show moderate progression of the disease and five members of the group are in an advanced stage of leprosy.