a statement of what the researcher believes to be true, at the end of the study the researcher decides whether the evidence collected supports the hypothesis or not
null hypotheses
a statement of no effect. for example “there is no difference in the marks on class tests between people who sleep an average of 8 hours per night and those with a lower sleep average.”
alternative hypotheses
the alternative to the null hypotheses, any hypotheses except the null.
confederate
an individual in a study who is not a real participant and has been instructed how to behave by the investigator
directional hypotheses
states the direction of the predicted difference between two conditions or two groups of participants
experimental hypotheses
the term used to describe the alternative hypotheses in an experiment
non-directional hypotheses
predicts simply that there is a difference between two conditions or two groups of participants, without stating the direction of the difference
pilot study
a small-scale trial run of a study to test any aspects of the design, with a view to making improvements
