Thank you for giving the clarification of the randomized control trial, but could you give us an example?

You are welcome.

Yeah, it is much clearer. Thank you!

This might help. Let’s look at the impact of cognitive behavioral therapy (CBT) on people suffering from depression: we may hypothesize that depressed people receiving CBT would improve more (that is, have a reduction in their depression) than those not receiving CBT. In this case, one group of depressed people would receive CBT (the experimental group) and the other would not (the control group). The key point is to allocate people to each of the two groups randomly. Significant importance is also ascribed to preventing either group from being affected by other factors which might impact the change which would occur. Finally, measurements are taken at (at least) two points, a baseline and the follow-up point, and the two groups are compared to see whether the improvement in the experimental group is greater.