Exam 7: Experiments

Internal validity in experiments is weakened by noncomparability of groups.

Newsworthy events that have to do with the focus of an experiment and major disasters to which subjects are exposed are examples of ______.

True experiments utilize comparison groups because they help reduce which of the following threats to internal validity?

Differential attrition in comparison and experimental groups creates what type of internal invalidity?

Whenever there is reason to think that taking the pretest may itself influence how participants react to the treatment,this design should be considered.

Before-and-after designs have no control or comparison groups.

Participants were chosen to take part in a study based on how poorly they engaged with the teacher and their learning material in class.During the study,researchers noted a vast improvement in students who did not engage regularly in class.However,when placed back in their regular classroom setting,the students' behavior regressed back to normal.Which of the following best fits what is happening to these children?

While participating in a lengthy experiment involving job training for welfare recipients,the economy enters into a major recession.Posttest measurements found that job training was unsuccessful in helping participants locate jobs.However,the experiment's designers claim that the findings were inconclusive because of internal invalidity.Which of the following sources of internal invalidity would they be most likely to name as the problem?