Placebo - a treatment that looks like the real treatment, but actually has no effect on the dependent variable.
Experimental group - a sample of people which receive an active treatment.
Replication - repeating the experiment under identical conditions.
Double blind trial - where neither participants nor researchers are aware of who is in the control group and who are in experimental groups.
Randomisation - the allocation of participants to the 2 groups in a random way.
Treatment - an aspect of the experiment that is to be completed.
Blind trial - an experiment where the participants are unaware whether they are in the control group or the experimental group.
Control group - receives no active treatment.
Experimental error - the variation in the dependent variable that arises from other sources other those taken into connsideration.
Paired comparison - a simple experimental design when 2 treatment are being compared.
What is the purpose of replication?
Ensures that a single value does not include experimental error, the more replications done, the less chance of experimental error.
What is the purpose of double blind trial?
Staff involved as well as patient do not know whether the treatment contains the drug or not. This means the attitude of staff is not influenced by knowledge of the drug.
What is the purpose of randomisation?
To eliminate bias - if randomisation has not occurred, conclusions are unreliable.
What is the purpose of paired comparison?
Minimises individual variation between tested samples, reducing experimental error.
What is the purpose of blind trial?
Patients do not know whether their treatment contains the drug or not so patients results are not affected by their expectations.
