9. evaluation techniques


9.5 In defining an experimental study, describe
(a) how you as an experimenter would formulate the hypothesis to be supported or refuted by your study
(b) how you would decide between a within-groups or between-groups experimental design with your subjects

answer available for tutors only


  • Determining independent variables or variables that can be controlled by the experimenter and will determine the number of experimental conditions, based on the number of different levels of all independent variables that will be tested.
  • Determining the dependent variables or phenomena that can be measured for subjects in the various experimental conditions.
  • Phrasing the hypothesis of the experiment in terms of an expected relationship between the independent and dependent variables.

(b) Deciding on the experimental design, in terms of within-groups or between-groups design, depends on the kinds of subjects you will use, how many resources are available for experimentation and the problems associated with learning effects. A within-groups design will require fewer subjects (and therefore be cheaper in terms of cost and time) but may exhibit bad learning effects if the experiment is not carefully designed. Students should demonstrate that they know the difference between within- and between-groups design. The former has each subject tested under all experimental conditions. Between-groups has each subject tested under only one condition.

Other exercises in this chapter

ex.9.1 (ans), ex.9.2 (ans), ex.9.3 (ans), ex.9.4 (ans), ex.9.5 (ans), ex.9.6 (tut), ex.9.7 (tut), ex.9.8 (open), ex.9.9 (tut)

all exercises for this chapter