Question

There are two main classes of individuals who can affect the outcome of an experiment:

Those who could influence the results
Those who evaluate the results
When all the individuals in either one of these classes are blinded, an experiment is said to be:

A) Single blind (I'm thinking this?)
B) Double blind
C) not blinded
D) biased

Answer 1

Revise your thinking.

1. <B>Single blind</B> gives the control group a <B>placebo</B> — a substance that is inert, it has no physical effect. Subjects don't know if they are in experimental or control group to reduce placebo effect, a change in behavior solely due to believing that you are getting the independent variable.

2. <B>Double blind</B> keeps both subjects and experimenter ignorant of group setup. Distribution of the independent variable and placebo are controlled by third party. This controls for experimenter bias and <B>self-fulfilling prophecy</B>, which means that experimenters with particular expectations are likely to consciously or unconsciously to bias the experiment and influence it to conform to their expectations.