Question 1

The manager of a Dairy Products Division wants to test the effects of the "buy one,get one free" sales promotion on the sale of the company-owned brand of packaged cheese,for a week.She records the sales of the packaged cheese during the previous 2 weeks to assess the effect of the promotion.However,on the very day that her sales promotion goes into effect,the Dairy Farmer's Association unexpectedly launches a multimedia advertisement on the benefits of consuming dairy products,especially cheese.The sales of all dairy products,including cheese,go up in all stores,including the one where the experiment had been in progress.Here,because of unexpected advertisement,one cannot be sure how much of the increase in sales of the cheese in question was due to the sales promotion and how much to the advertisement of the Dairy Farmers' Association! In this case,___________ have reduced the internal validity or the faith that can be placed on the conclusion that the sales promotion caused the increase in sales.

Accepted Answer

The unexpected advertisement by the Dairy Farmers' Association is an external factor that could have affected the sales of the company-owned brand of packaged cheese. This is an example of a history effect, which refers to external events that occur during the study that could affect the outcome, and therefore reduces the internal validity of the study.

Question 2

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.

Accepted Answer

A more sophisticated experimental design can include techniques such as randomization, blinding, and control groups to reduce biases and increase internal validity.

Question 3

Interactive testing and selection effects may restrict the internal validity of our findings.

Accepted Answer

The answer of Interactive testing and selection effects may restrict...

Question 4

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?

Accepted Answer

A factorial design would be appropriate for testing the effects of both the type of vehicle used and the fare reduction on passenger increases. This design would allow for the manipulation of two independent variables (vehicle type and fare reduction) and allow the researcher to examine their separate and combined effects on the dependent variable (passenger increases).

Question 5

Whereas the randomized block design helps the experimenter to minimize the effects of one nuisance variable in evaluating the treatment effects,the Latin square design is very useful when two nuisance blocking factors are to be controlled.

Accepted Answer

The statement accurately describes the purposes and benefits of both randomized block and Latin square designs in experimental design.

Question 6

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

Accepted Answer

The crucial difference between a quasi-experimental design and a true experimental design is the ability to control variables. In a true experimental design, researchers have control over all variables except for the independent variable, which allows for the establishment of cause-and-effect relationships between variables. Quasi-experimental designs lack this level of control and therefore cannot establish causation with the same degree of confidence as true experimental designs. The level of sophistication and costs can vary between both types of designs and are not defining differences.

Question 7

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

Accepted Answer

A factorial design allows for the manipulation of two or more independent variables and the examination of their effects on a dependent variable simultaneously.

Question 8

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

Accepted Answer

Instrumentation effects can occur when there is a change in the measuring instrument used to collect data between the pretest and posttest. This change can lead to different results being observed, even if there has been no change in the underlying construct being measured. Therefore, it is important to use the same instrument at both time points to minimize instrumentation effects.

Question 9

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

Accepted Answer

Deceiving subjects is a violation of the principle of informed consent and is considered unethical in research. Subjects have the right to know the true purpose of the research and to give their voluntary consent to participate.

Question 10

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

Accepted Answer

Mortality, maturation, and instrumentation effects are common threats to internal validity that can impact the accuracy of research findings.

Question 11

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

Accepted Answer

A pre-test and post-test experimental group design is a true experimental design because it involves random assignment of participants to groups, allowing for control over extraneous variables.

Quiz 9: Experimental Designs