A researcher wants to study the effect of 4 different treatment regimens on cell development in fetal rat heart muscle cells. The treatments included a control as well as three combinations of growth inhibitors and enhancers at different stages of fetal development. Each treatment was assigned to a randomly selected petri dish containing a sheet of muscle cells harvested from genetically similar mice.
10 7-day old cells were harvested from each dish and measured for morphological development. The treatments were then applied and after 3 days, 10 additional 10-day old cells were harvested from each petri dish and the cells were measured for morphological development. A measure of relative growth was recorded for each dish.
Record your answers to the following questions. Discuss the answers with your group and submit your work.
What is the treatment? What is the experimental unit? What is the observational unit? Are there any problems with the experimental setup? How would you have designed the experiment?