Question

in an experiment determining the effects of antibiotics on the treatment of pneumonia in mice, two groups of mice with pneumonia are compared. one group, group a, receives no antibiotic, and the other group, group b, receives 10 mg/kg of body weight of a new antibiotic. besides the administration of the antibiotic, there are no differences between the two groups of mice. what is the purpose of group a?

to ensure that the experiment is statistically valid
to measure how much antibiotic is most effective in treating pneumonia in mice
to ensure that only the treatment with antibiotics affects the pneumonia
to calculate an approximate concentration of antibiotic to use in treating pneumonia in humans

Explanation:

Group A is a control group. In an experiment, a control group is used to isolate the effect of the variable being tested (the antibiotic in this case). By having a group with no antibiotic treatment while keeping other factors the same, researchers can determine that any changes in group B are due to the antibiotic and not other variables.

Answer:

to ensure that only the treatment with antibiotics affects the pneumonia