Final answer:
An example of an independent-groups posttest-only design is a study comparing the test scores of two groups of students taught using different methods, where one group uses a traditional method and the other a new method. Option 1
Step-by-step explanation:
An independent-groups posttest-only design is a type of experimental design where subjects are randomly assigned to two different groups. One group is the experimental group, which receives the treatment or is exposed to the independent variable being studied.
The other is the control group, which does not receive the treatment. The researcher only measures the outcome, or dependent variable, after the treatment has been applied, without comparing it to measurements taken before the treatment (pretest).
An example of an independent-groups posttest-only design would be option 1) from your list: A study comparing the test scores of two groups of students who were taught using different teaching methods. Here, one group might receive instruction through traditional teaching methods, while the other group is taught using a new, innovative approach.
At the end of the study period, test scores for both groups are collected and compared to see if there is a significant difference attributable to the teaching method used, which is the independent variable.
In the study you mentioned, where a pretest and posttest are administered to assess the effectiveness of a new math textbook, the groups would not be considered independent or matched because there is only one group that is given both tests. In that study, it seems the same students are tested before and after using the textbook. This would be more aligned with a pretest-posttest single group design rather than an independent or matched groups design. Option 1