2. (a) What is the main purpose of collecting data by experimentation? (b) What is the main factor that decides what type of experimental method to apply in a given circumstance? (c) Name the four experimental methods discussed in the class. (d) A clinical trial was a completely randomized design experiment that as- signed 240 patients at random among four treatment combinations as follows: Steroid spray Placebo spray Antibiotic pill Placebo pill 53 64 60 63 (1) What is the experimental unit? (ii) How many factors are in this clinical trial? (ii) Explain briefly how you would carry out a randomization scheme in this experiment. And under what assumption? 2. (a) What is the main purpose of collecting data by experimentation? (b) What is the main factor that decides what type of experimental method to apply in a given circumstance? (c) Name the four experimental methods discussed in the class. (d) A clinical trial was a completely randomized design experiment that as- signed 240 patients at random among four treatment combinations as follows: Steroid spray Placebo spray Antibiotic pill Placebo pill 53 64 60 63 (1) What is the experimental unit? (ii) How many factors are in this clinical trial? (ii) Explain briefly how you would carry out a randomization scheme in this experiment. And under what assumption