Step 1

To find,

The ideal study design from a statistical point of view?

Step 2

Result:

Clinical trials is dividdin to two parts trials and observational study.

Clinical trial is experimental study so it is also ideal study from a statistial point of view.

So, both the clinnil trial and observational study are ideal study design from a statistcal point of view.

Answer should be A and B

To find,

The ideal study design from a statistical point of view?

Step 2

Result:

Clinical trials is dividdin to two parts trials and observational study.

Clinical trial is experimental study so it is also ideal study from a statistial point of view.

So, both the clinnil trial and observational study are ideal study design from a statistcal point of view.

Answer should be A and B