Exploring the Logic of Experimental Design
1. Jackson even-numbered Chapter Exercises (p. 244)
#2. What possible confounds can you identify in this study?
There are three confounds in the health magazine depression study that might have impacted the study and the observed findings. First, there does not appear to be a control group. The study was for nine months long, mortality within the length of the study could have an effect. To conduct this kind of study, however, requires many more subjects and may be more difficult to match relevant subjects, making it more susceptible to mortality confounds as well" (By matching participants in this way groups can be made, n.d.). If the subjects that dropped out were the most depressed, it would be …show more content…
What are confounds? Give an example of a design that has three confounds. Describe three ways to alter the design to address these confounds and explain the advantages and disadvantages of each.
A confound is a circumstance that was not controlled in the directing of the experiment; an ambiguous variable that caused an effect to happen. One of the conditions necessary for confounding to occur is that the confounding factor must be distributed unequally among the groups being compared. A case of a design that has three confounds would be like the one mentioned by Jackson (2012). Confounding occurs when two variables systematically vary in correlation with another related variant (Kovera, 2010, p. 2).
In the earlier design by Jackson (2012), it is hard to know if the treatment was responsible for the measured result. In this design, it is conceivable to discover that there is a difference because of the application of the treatment; randomization permits the researcher to assume probabilistic identicalness between the groups. This design enhances internal validity because it is more grounded than any single group design, and is verified against multiple-group threats as well except mortality. This design does not secure against social threats to internal validity (Trochim, Donnelly, & Arora, …show more content…
Half would be the control group; randomly selected and would receive no instructions regarding the purpose of the study. They would use a mood instrument at the culmination of the experiment. The other half, the experimental group would be instructed to smile throughout the experiment and be administered the same mood instrument. These two groups allow for comparison of results to determine if there is a positive effect between the two groups. These groups, minimize the likelihood of confounds of testing effects. The disadvantage of this design is that it requires sufficient participants for groups to be equivalent.
If we use a within-subject design, a single group of subjects is given a random assignment then assessed for mood. After the primary assessment, subjects would receive the opposite instructions and mood would be assessed again toward the end of the experiment. Measuring the subjects in two conditions, eliminates the possibility of differences between groups. Having the assessments administered twice could be a disadvantage that could result in confounds due to testing
1. Jackson even-numbered Chapter Exercises (p. 244)
#2. What possible confounds can you identify in this study?
There are three confounds in the health magazine depression study that might have impacted the study and the observed findings. First, there does not appear to be a control group. The study was for nine months long, mortality within the length of the study could have an effect. To conduct this kind of study, however, requires many more subjects and may be more difficult to match relevant subjects, making it more susceptible to mortality confounds as well" (By matching participants in this way groups can be made, n.d.). If the subjects that dropped out were the most depressed, it would be …show more content…
What are confounds? Give an example of a design that has three confounds. Describe three ways to alter the design to address these confounds and explain the advantages and disadvantages of each.
A confound is a circumstance that was not controlled in the directing of the experiment; an ambiguous variable that caused an effect to happen. One of the conditions necessary for confounding to occur is that the confounding factor must be distributed unequally among the groups being compared. A case of a design that has three confounds would be like the one mentioned by Jackson (2012). Confounding occurs when two variables systematically vary in correlation with another related variant (Kovera, 2010, p. 2).
In the earlier design by Jackson (2012), it is hard to know if the treatment was responsible for the measured result. In this design, it is conceivable to discover that there is a difference because of the application of the treatment; randomization permits the researcher to assume probabilistic identicalness between the groups. This design enhances internal validity because it is more grounded than any single group design, and is verified against multiple-group threats as well except mortality. This design does not secure against social threats to internal validity (Trochim, Donnelly, & Arora, …show more content…
Half would be the control group; randomly selected and would receive no instructions regarding the purpose of the study. They would use a mood instrument at the culmination of the experiment. The other half, the experimental group would be instructed to smile throughout the experiment and be administered the same mood instrument. These two groups allow for comparison of results to determine if there is a positive effect between the two groups. These groups, minimize the likelihood of confounds of testing effects. The disadvantage of this design is that it requires sufficient participants for groups to be equivalent.
If we use a within-subject design, a single group of subjects is given a random assignment then assessed for mood. After the primary assessment, subjects would receive the opposite instructions and mood would be assessed again toward the end of the experiment. Measuring the subjects in two conditions, eliminates the possibility of differences between groups. Having the assessments administered twice could be a disadvantage that could result in confounds due to testing