Experimental Studies in Psychology Use Blinding to Prevent Researchers from Biasingtheir

Essay

Experimental studies in psychology use blinding to prevent researchers from biasingtheir measurements of subjects in the study. In a study of a psychotherapeuticintervention, a blinded clinician was asked to guess what treatment each subjectreceived. Data from that experiment are shown below. Suppose a subject is to bechosen at random from the subjects in this study.
a) What is the probability that the clinician made a correct guess for the selectedsubject?
b) What is the probability the selected subject will have had therapy?
c) What is the probability the selected subject will be one for whom the cliniciancorrectly guessed had therapy?
d) What is the probability the selected subject will be one for whom the clinicianguessed correctly or who received the placebo treatment?
e) What is the probability the selected subject will be one for whom the clinicianguessed correctly and who received the placebo treatment?
f) In a few sentences, explain why the probabilities calculated in parts (d) and (e)differ.