Answer
a) This is an example of a designed experiment because the physicians controlled the assignment of patients into two respective groups, the treatment group and the control group. What is more, the physicians used the procedure of randomization to assign the patients into different groups. The conclusion is invalid because the physicians have access to information regarding which patients belong to treatment groups or control groups, as a result they will form biases.
b) It is a designed experiment because the experimenter controls the assignment of elements into different groups in random manner.
c) It is not a double blind experiment, because the physicians have access to information regarding which patients belong to treatment or control groups.
Work Step by Step
a) This is an example of a designed experiment because the physicians controlled the assignment of patients into two respective groups, the treatment group and the control group. What is more, the physicians used the procedure of randomization to assign the patients into different groups. The conclusion is invalid because the physicians have access to information regarding which patients belong to treatment groups or control groups, as a result they will form biases.
b) It is a designed experiment because the experimenter controls the assignment of elements into different groups in random manner.
c) It is not a double blind experiment, because the physicians have access to information regarding which patients belong to treatment or control groups.