A group of students performed an experiment to see whether doing
jumping jacks for two minutes would increase their blood pressure. They
had five students perform jumping jacks for two minutes and then
measured their blood pressure. They repeated the experiment three
times. They analyzed their results, and since the blood pressure
measurements were all above the normal values you'd expect, they
concluded that doing jumping jacks does increase blood pressure. What
was wrong with their experiment?
They didn't include a control group
O
They didn't include multiple trials
They included more than one independent variable
O
They should've only had one test subject​