Exam 8: Experiments

Studying the effects of a disaster,such as Hurricane Katrina,is considered a natural experiment.

Cornelia used the student directory at her school to select a random sample of 100 students for her laboratory experiment on decision making.She then used a quota matrix containing the variables she felt would most likely influence decision making,and assigned people within each matrix cell alternately to the experimental and control groups.What method of selecting subjects was used?

When events (e.g.life stressors)outside of the researcher's control have the likelihood to affect a participant's response,especially in longitudinal studies,this threat to validity is

You have just been employed by a major financial company for your skills in boosting employee morale.Describe how you would go about testing whether your skills and methods have led to an increase in employee morale.Be certain to explain any issues you may encounter in your goal,as well as the strengths and weaknesses of the design that you use.

The problem of external validity refers to the generalizability of results.

In evaluating how effective an anti-bullying program in a school is,Iori asks students how many times they have been bullied in the past four months at the beginning and middle of the semester.However,since he did not use a control group,what form of invalidity may be a problem?

Subject "mortality" is usually a greater problem in experiments that have a long duration than in experiments that have a short duration.

Igor wanted to do an experiment testing the effects of a new classroom strategy for teaching reading on the reading skills of elementary school students.He used random assignment and wanted to make sure that neither the subjects nor the experimenters knew which was the experimental group and which was the control group.It would be best to use the

Which design addresses the problem of testing interaction with the stimulus?

Researchers tend to use probability samples to recruit subjects for the experimental and control groups.

As a longitudinal experiment,Juan worked with two different groups,one who was receiving a special stress-reduction training,and another who was not.These two groups were matched together on important variables,and a pretest and posttest were both performed.However,he noticed that after sessions the individuals in the stress-reduction training were telling those in the control group about what they did each day.What form of internal invalidity is this?

From a scientific perspective,the preexperimental design that provides the weakest evidence of a relationship between dependent and independent variables is the

The posttest-only control group most closely represents which preexperimental design?

Howard Schuman argues that experimental research can be specifically useful in helping with what other form of research?

Laboratory experiments are only useful in the natural sciences and psychology

What differentiates experimental from preexperimental designs? Give an illustration of a situation in which an experimental design would be preferred and one in which a preexperimental design would be preferred.

Martin performed an experiment at the local university.Students were measured on their views towards stem cell research,then shown a documentary on the topic.After the film,the students were given a survey to measure their opinion.This survey after the movie is an example of a(n):

A research study that features both an experimental and control group,as well as pre-and post-tests for each,is an example of a(n)

The question of internal validity refers to

The greatest weakness of a controlled laboratory experiment is its artificiality.