After stinging its victim, the honeybee leaves behind the barbed stinger, poison sac and muscles that continue to pump venom into the wound. Visscher et al. (1996) compared the effects of two methods of removing the stinger left behind: scraping off with a credit card or pinching off with thumb and index finger. A total of 40 stings were induced on volunteers. Twenty were removed with the credit card method and 20 were removed with the pinching method. The size of the subsequent welt by each measurement came from two volunteers (both authors of the study), each of whom received one treatment 10 times on the one arm and the other treatment 10 times on the other arm. Pinching led to a slightly smaller average welt, but the difference between the methods was not significant. 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 credit card method.
2. Yes, the control group is the group receiving pinching method.
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 the credit card method with people of similar age, gender, and overall health that used the pinching method 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
1. 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 study that employed matching and 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
1. Randomized block design
2. Completely randomized design
3. Double-blind
4. Single-blind