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Experimental design is of critical importance to a successful experiment. The images below represent several potential experimental designs. There are two treatments represented by the colors red and blue. Circles represent samples to be analyzed. Squares represent incubation chambers where the samples are kept. If no square is present, the samples are kept within a single chamber. Which of the following experimental designs are acceptable for testing the effects of red and blue treatments? C]_ C]_ C] I O 8 . . . . . ..Michalsen et al. (2003) conducted a study to examine the effects of "leech therapy" for pain resulting from osteoarthritis of the knee. Two treatments were randomly assigned to 51 patients with osteoarthritis of the knee. Patients in the leach treatment received 4-6 medicinal leeches applied to the soft tissue of the affected knee in a single session. The animals were left to feed ad libitum until they detached themselves, on average 70 minutes later. Patients in the control treatment were given dichlofenac gel and were told to apply it twice daily to the affect area. Pain was assessed by a questionnaire given by personnel unaware of the treatments applied to each patient. The results showed that seven days after the start of treatment, pain was significantly lower in the leech group. Does this study include a control group? Enter the number of the best answer choice from the options below 1. Yes, the control group is the group receiving the dichlofenac gel. 2. Yes, the control group is the group receiving leech therapy. 3. Yes, the control group is the group receiving no therapy. 4. No, there was no control for this experiment. Is this an observational study or experimental research? Enter the number of the best answer choice from the options below. 1 . It is an observational study because the treatments were not randomly assigned. 2. It is an observational study that used matching to pair people who had received leach therapy with people of similar age, gender, and overall health that used dichlofenac to minimize bias. 3. It is experimental research, participants were randomly assigned to treatment groups, one of which served as a control. Is this experiment completely randomized design or randomized block design? Enter the number of the best answer choice from the options below 'I . The two treatments were applied to separate groups of randomly assigned patients; therefore, it is completely randomized design. 2. The patients were blocked into groups based on when they received treatment and they were randomly assigned a treatment type; therefore, this research is a randomized block design. 3. This is an observational studywhere neither a completely randomized design, nor a randomized block design. Which strategy that may have helped reduce bias was not employed in this study? Enter the number of the best answer choice from the options below 'I . Randomized block design 2. Completely randomized design 3. Doubleblind 4. Singleblind The antibody production of 12 male red-winged blackbirds before and after receiving testosterone implants was compared. The units for antibody levels were natural log (10'3 optical density) per minute (ln(mOD/min)). The mean change in antibody production was d = 0.056, and the standard deviation was sd = 0.244 If you were assigned the task of repeating this experiment, and wanted to ensure that you could detect a mean change of 0.07 units with a probability of 0.8, then what sample size would you use? Since we are calculating n for a study of individuals, answers should be rounded to the closest whole number