Consider an experiment in which participants take a pill that is either a medication or a placebo. the researchers want to determine the effect of the medication on depression. in this example, the control group would be

The control group in an experiment where there is a placebo present is the group taking the placebo. With depression you want to see noticeable changes in a person on new medication to see how they will react. Although the placebo group won't know it's a placebo there still could be some noted effects but for the most part the placebo group should remain mostly unaffected and therefore is the control.

When two vehicles meet on a steep road where neither can pass: the vehicles going downhill must back up or simply must yield the right of way so it can pass : )

At 8.5% i am making after one year 1,500   +  1,500 x 0.08 = $1,620

my credit card cost 1,600 + 1,600 x 0.19 = $1,904


total balance =  interest  (negative)  of credit card + interest earn (positive)

that is  -304 + 120 = -$181