11)A well-developed research design A)is not necessary for high-constraint research projects. B)will evolve during the course of an experiment. C)is essential before beginning any observations of an experiment. D)is only necessary for beginning researchers. 12)Planning the research design is a crucial step A)only in experimentation. B)at all levels of research. C)at all levels of research higher than the correlational level. D)only when statistical analyses are included 13)The statement “variation is necessary to carry out experiments” A)is true only in experiments involving human participants. B)is not true in nearly 30% of all experimentation. C)refers only to the importance of having very different participants in each group. D)is always true in experiments of any kind. 14)An experimenter hopes to find that the predicted variation A)leads to accepting the null hypothesis. B)reduces the difference between-groups. C)increases the within-groups variation. D)is due to the experimental manipulation. 15)In order to study causal relationships, A)the null hypothesis must not be rejected. B)external validity is essential. C)we must use a t-test or F-test. D)there must be variation of the independent variable. 16)Extraneous variation generally A)reduces internal validity. B)enhances internal validity. C)has no effect on internal validity. D)affects internal validity only when there are more than two levels of the independent variable. 17)One basic purpose of experimental design is A)to reduce the number of participants needed. B)to control variance. C)to keep the alpha level below .05. D)to observe contingencies. 18)Without ________, there would be no differences between groups to test. A)nonmanipulated independent variables B)degrees of freedom C)uniformity D)variation 19)In order for us to study causal relationships among variables, it is necessary for A)the independent variable to demonstrate variation. B)the dependent variable to be a constant. C)the independent variable to demonstrate that it is randomly distributed. D)there to be extraneous variation. 20)Error variance is A)between-groups variance. B)within-groups variance. C)between-groups variance divided by within-groups variance. D)the major component causing differences between experimental conditions. Â