In which of the following research methods is the subject and the experimenter interacting with subjects is blind to the condition of the subject?

The research method in which both the subject and the experimenter interacting with subjects are blind to the condition of the subject is known as a Double-Blind Study.

Here are the steps explaining this method:

1. In a double-blind study, neither the participants nor the experimenters know who is receiving a particular treatment. This procedure is utilized to prevent bias in research results.

2. Double-blind studies are particularly useful for preventing bias due to demand characteristics or the placebo effect.

3. The first step in a double-blind study is to form two groups: a test group and a control group.

4. The test group receives the treatment or intervention, and the control group does not. However, neither the participants nor the researchers know which group is which.

5. The researchers collect data without knowing which participants belong to which group. This helps to ensure that the results are due to the treatment or intervention itself, and not due to bias on the part of the researchers or the participants.

6. Once the data has been collected, the researchers can then determine which group received the treatment and analyze the results accordingly.