BTM8106 Week 1,2,3,4,5,7,8 Complete Solutions
Topseller1.Jackson (2012) even-numbered Chapter Exercises (p. 244). You read in a health magazine about a study in which a new therapy technique for depression was examined. A group of depressed individuals volunteered to participate in the study, which lasted 9 months. There were 50 participants at the beginning of the study and 29 at the end of the 9 months. The researchers claimed that of those who completed the program, 85% improved. What possible confounds can you identify in this study? What are internal validity and external validity, and why are they so important to researcher?
Research has a bias since they are not taking into account the total number of participants. They are not considering the complete sample. It is important to have a complete validity of data for better analysis. Complete analysis of sample needs to be taken into account. Integrity in the field of academics is crucial not only inside the university but also for maintaining the level of trust in the minds of the people. It is upto the researchers to maintain the integrity and the brand image of the university.
2.What is the purpose of conducting an experiment? How does an experimental design accomplish its purpose?
Kant in 1793 proposes something that went on rampage and is now known worldwide. The saying was
“Some things are fine in theory, but do not work in practice”
This rule is applicable even after centuries. Now people understand that theory and then application of the same in real like is not very easy. Identifying something in theory is somewhat easy. It just needs some logic and nothing else whereas, application of the same in theory is very different. When a person starts applying a theory into actual practice, the real test starts and it is not very easy to pass through. There will be many hurdles that a person needs to pass.
3.What are the advantages and disadvantages of an experimental design in an educational study?
Biggest advantage is related to the fact that the experimental design helps in analysing the difference between fact and the theory and the practical implementation of the same.
· To describe the characteristics of relevant groups, such as consumers, salespeople, organizations, or market areas.
· To estimate the percentage of units in a specified population exhibiting a certain behavior.
· To determine the perceptions of product characteristics.
· To determine the degree to which marketing variables are associated.
· To make specific predictions.
4.What is more important in an experimental study, designing the study in order to make strong internal validity claims or strong external validity claims? Why?
It is important to balance the two. According to stats direct:
Internal validity
This is about the validity of results within, or internal to, a study. It usually concerns causality, i.e. the strength of assigning causes to outcomes. For laboratory experiments with tightly controlled conditions, it is usually easy to achieve high internal validity. For studies in difficult to control environments, e.g. health services research, it can be difficult to claim high internal validity. When you claim high internal validity you are saying that in your study, you can assign causes to effects unambiguously. Randomisation is a powerful tool for increasing internal validity - see confounding.
In the context of questionnaires the term criterion validity is used to mean the extent to which items on a questionnaire are actually measuring the real-world states or events that they are intended to measure. This type of internal validity could be assessed by comparing questionnaire responses with objective measures of the states or events to which they refer; for example comparing the self-reported amount of cigarette smoking with some objective measure such as cotinine levels in breath.
External validity
This is about the validity of applying your study conclusions outside, or external to, the setting of your study. Another term for this is generalisability. Sometimes this is obvious, for example a public opinion poll taken at the entrance to a football match would not be properly representative of the general population. Often it is less obvious, for example a study in medical settings on a Monday morning will not be representative of the pattern of illnesses seen at other times of the week. A key to improving external validity is to understand the setting thoroughly before you embark upon the study.
5.In an experiment, what is a control? What is the purpose of a control group? Of single or multiple comparison groups?
Control means the level of significance an experiment.
Control group helps in comparing various groups in the experiment. A single hypothesis is tried for rejecting or acceptance in the experiment.
6.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. Confounds means creating confusion in the experiment. When irrelevant data is added into the relevant data, confusion creeps into the experiment.
In the words of South Alabama university:
Potential confounding variables can be controlled for by using of one or more of a variety of techniques that eliminate the differential influence an extraneous variable may have for the comparison groups in a research study.
· Differential influence occurs when the influence of an extraneous variable is different for the various comparison groups.
· For example, if one group is mostly females and the other group is mostly males, then the gender may have a differentially effect on the outcome. As a result, you will not know whether the outcome is due to the treatment or due to the effect of gender.
· If the comparison groups are the same on all extraneous variables at the start of the experiment, then differential influence is unlikely to occur.
· In experiments, we want our groups to be the same (or “equivalent” on all potentially confounding extraneous variables). The control techniques are essentially attempts to make the groups similar or equivalent.
7.What does “cause” mean and why is it an important concept in research? How are correlation and causation related? A good hypothesis is a question(s) that would be answered with the data to be collected. The goal is to develop a hypothesis that is practical and testable. This the cause and the research try to prove it right or wrong.
8.You are a researcher interested in addressing the question: does smiling cause mood to rise (i.e., become more positive)? Sketch between-participants, within-participants, and matched-participants designs that address this question and discuss the advantages and disadvantages of each to yielding data that help you answer the question.
In between participants all the participants are researched and data is then compared.
In within subject, repeated research and use of statistical tools is the norm.
In matched participants, different participant in each group are researched.
Reference: http://www.ablongman.com/graziano6e/text_site/MATERIAL/sg/sg11su.htm