Do multivitamin supplements improve health? To answer this question, researchers recruited 2000 adults, all were provided with supplies of capsules and were asked to take one capsule per day. One thousand of the adults received capsules that were multivitamin supplements and one thousand received capsules that were a placebo. The researchers used an extensive questionnaire to assess the health of all participants at the start of the study and after two years into the study. Outline the design of this study using a diagram  

  Identify possible lurking variables in the experiment in question 1.

 Based on the information given, do you think the experiment in question 1 was well designed? Answer this question by addressing each of the three principles of experimental design (control, randomize, use enough subjects).