Identify the Type of Observational Study (Cross-Sectional, Retrospective, Prospective)

Essay

Identify the type of observational study (cross-sectional, retrospective, prospective).
-A researcher conducts an experiment to determine whether acupuncture can help people to recover from back
injuries. Participants are randomly assigned to a treatment group or a control group. Over a period of three
weeks, those assigned to the treatment group receive acupuncture treatments. At the end of the three weeks, the
improvement reported by those in the treatment group is compared with the improvement reported by those in
the control group. In this experiment there is no blinding. What does this mean and why could this cause a
problem?