A group of twenty-five Labrador retrievers and their owners, are brought to the research lab one by ...

ANS: B
The one-group posttest-only design is referred to as pre-experimental rather than quasi-experimental because of its weaknesses and the numerous threats to validity. In this type of study, subjects are only tested after the treatment; the group is not pretested therefore, there is no direct way to measure change. The one-group pretest-posttest design, is one of the more commonly used designs; in it there is an experimental group that undergoes some form of pretesting prior to treatment (the manipulation of the independent variable) and then is subjected to posttesting after the treatment. In the pretest and posttest design with a comparison group, both the experimental group and the comparison group are tested before the experimental group is treated and after it. The pretest and posttest design with removed-treatment, even though it uses only one group, creates conditions that approximate the conceptual requirements of a control group receiving no treatment. The design is basically a one-group pretest-posttest design. However, after a delay, a third measure of the dependent variable is taken, followed by an interval in which the treatment is removed, followed by a fourth measure of the dependent variable.