Exam 9: Experimental Designs

The manager of a bus company is interested in knowing passenger increases if he used three different types of bus (Luxury Express,Standard Express,Regular)and manipulated both the fare reduction and the type of vehicle used,simultaneously. Which of the following research designs is appropriate?

A pre-test and post-test experimental group design is an example of a quasi experimental design.

What is true about Quasi-Experimental Designs?

A factorial design enables us to test the effects of two or more variables at the same time on the dependent variable.

Manipulation means that we create different levels of the independent variable to assess the impact on the dependent variable.

Instrumentation effects might arise because of a change in the measuring instrument between pretest and posttest.

A main testing effect occurs when the prior observation (the pre-test)affects the later observation (the post-test).

A field experiment,as the name implies,is an experiment done in the natural environment in which work goes on as usual,but treatments are given to one or more groups.

One way of controlling the contaminating or "nuisance" variables is to match various groups by picking the confounding characteristics and deliberately spreading them across groups.

It is possible to reduce biases that might affect the internal validity of experimental designs by enhancing the level of sophistication of the experimental design.

Main testing effects occur when the pre-test affects the participant's reaction to the treatment (the independent variable).

A major threat to validity in a "post-tests only with one experimental and one control group" is:

Internal validity refers to what extent would the results found in the lab setting be transferable or generalizable to the actual organizational or field settings.

The difference between matching and randomization is that in the former case individuals are deliberately and consciously matched to control the differences among group members,whereas in the latter case we expect that the process of randomization would distribute the inequalities among the groups,based on the laws of normal distribution.

The crucial difference between a quasi-experimental design and a true experimental design is:

In "matching groups",the process by which individuals are drawn (i.e. ,everybody has a known and equal chance of being drawn)and their assignment to any particular group are both random.

Deceiving subjects by deliberately misleading them as to the true purpose of the research is considered unethical.

Cause-and-effect inferences can also be contaminated by the effects of the passage of time.Such contamination is called history effects.

Mortality,maturation,and instrumentation effects may restrict the internal validity of our findings.

External validity refers to the confidence we place in the cause-and-effect relationship.