PART1-Due Thursday !!!! Respond to the following in a minimum of 175 words:
A researcher is investigating verbal behavior among introverts and extroverts. The researcher first tests participants and classifies them as either introverted or extroverted. She then randomly assigns participants to a high anxiety or a low anxiety social group and observes the number of words spoken by participants. The researcher wants to learn more about the effects of both personality style—introversion or extroversion—and social situation—high or low anxiety—on verbal behavior. In this case, verbal behavior is defined as the number of verbal communications uttered within a 5-minute observation period.
What type of design is this? Provide an example of a possible main effect that might emerge from this study. Additionally, provide an example of a possible interaction that might emerge
PART2- PLEASE SEE ATTACHMANENT!!! Select a research article of interest to you, preferably related to your Research Proposal, and use the Research Evaluation Worksheet to analyze the article. You can use this information to help form the literature review section of your research proposal.
PART3-PLEASE SEE PART 3 ATTACHMENT!!!Complete the Week Four Homework Exercise.
PART4-I AM ONLY RESPONSIBLE FOR ONE PART. I WILL POST ALL DETAILS ONCE THE TEAM LEADER NOTIFIES US ON WHAT PART WE ARE RESPONSIBLE FOR AND THE ARTICLES…
As a team, locate at least two surveys (you can use any survey that you find on the internet). Try to find one that is relatively brief —10 questions or less. Analyze the questions in the survey. Construct a table and evaluate each survey question on the following points:
negative wording
complexity (note: good questions are simple and straightforward)
double-barreled
loaded
grammatically incorrect
In your team, discuss the importance of writing good survey questions. How can poorly-written questions bias results? Submit both the table that you constructed as well as a copy of the survey you analyzed to your instructor.
REFERENCES
CHAPTER 8
LEARNING OBJECTIVES
Define confounding variable, and describe how confounding variables are related to internal validity.
Describe the posttest-only design and the pretest-posttest design, including the advantages and disadvantages of each design.
Contrast an independent groups (between-subjects) design with a repeated measures (within-subjects) design.
Summarize the advantages and disadvantages of using a repeated measures design.
Describe a matched pairs design, including reasons to use this design.
Page 162IN THE EXPERIMENTAL METHOD, THE RESEARCHER ATTEMPTS TO CONTROL ALL EXTRANEOUS VARIABLES. Suppose you want to test the hypothesis that exercise affects mood. To do this, you might put one group of people through a 1-hour aerobics workout and put another group in a room where they are asked to watch a video of people exercising for an hour. All participants would then complete the same mood assessment. Now suppose that the people in the aerobics class rate themselves as happier than those in the video viewing condition. Can the difference in mood be attributed to the difference in the exercise? Yes, if there is no other difference between the groups. However, what if the aerobics group was given the mood assessment in a room with windows but the video-only group was tested in a room without windows? In that case, it would be impossible to know whether the better mood of the participants in the aerobics group was due to the exercise or to the presence of windows.
CONFOUNDING AND INTERNAL VALIDITY
Recall from Chapter 4 that the experimental method has the advantage of allowing a relatively unambiguous interpretation of results. The researcher manipulates the independent variable to create groups and then compares the groups on the dependent variable. All other variables are kept constant, either through direct experimental control or through randomization. If the groups are different, the researcher can conclude that the independent variable caused the results because the only difference between the groups is the manipulated variable.
Although the task of designing an experiment is logically elegant and exquisitely simple, you should be aware of possible pitfalls. In the hypothetical exercise experiment just described, the variables of exercise and window presence are confounded. The window variable was not kept constant. A confounding variable is a variable that varies along with the independent variable; confounding occurs when the effects of the independent variable and an uncontrolled variable are intertwined so you cannot determine which of the variables is responsible for the observed effect. If the window variable had been held constant, both the exercise and the video condition would have taken place in identical rooms. That way, the effect of windows would not be a factor to consider when interpreting the difference between the groups.
In short, both rooms in the exercise experiment should have had windows or both should have been windowless. Because one room had windows and one room did not, any difference in the dependent variable (mood) cannot be attributed solely to the independent variable (exercise). An alternative explanation can be offered: The difference in mood may have been caused, at least in part, by the window variable.
Good experimental design requires eliminating possible confounding variables that could result in alternative explanations. A researcher can claim that the independent variable caused the results only by eliminating competing, Page 163alternative explanations. When the results of an experiment can confidently be attributed to the effect of the independent variable, the experiment is said to have internal validity (remember that internal validity refers to the ability to draw conclusions about causal relationships from our data; see Chapter 4). To achieve good internal validity, the researcher must design and conduct the experiment so that only the independent variable can be the cause of the results (Campbell & Stanley, 1966).
This chapter will focus on true experimental designs, which provide the highest degree of internal validity. In Chapter 11, we will turn to an examination of quasi-experimental designs, which lack the crucial element of random assignment while attempting to infer that an independent variable had an effect on a dependent variable. Internal validity is discussed further in Chapter 11 and external validity, the extent to which findings may be generalized, is the focus of Chapter 14.
BASIC EXPERIMENTS
The simplest possible experimental design has two variables: the independent variable and the dependent variable. The independent variable has a minimum of two levels, an experimental group and a control group. Researchers must make every effort to ensure that the only difference between the two groups is the manipulated (independent) variable.
Remember, the experimental method involves control over extraneous variables, through either keeping such variables constant (experimental control) or using randomization to make sure that any extraneous variables will affect both groups equally. The basic, simple experimental design can take one of two forms: a posttest-only design or a pretest-posttest design.
Posttest-Only Design
A researcher using a posttest-only design must (1) obtain two equivalent groups of participants, (2) introduce the independent variable, and (3) measure the effect of the independent variable on the dependent variable. The design looks like this:
images
Thus, the first step is to choose the participants and assign them to the two groups. The procedures used must achieve equivalent groups to eliminate any Page 164potential selection differences: The people selected to be in the conditions cannot differ in any systematic way. For example, you cannot select high-income individuals to participate in one condition and low-income individuals for the other. The groups can be made equivalent by randomly assigning participants to the two conditions or by having the same participants participate in both conditions. Recall from Chapter 4 that random assignment is done in such a way that each participant is assigned to a condition randomly without regard to any personal characteristic of the individual. The R in the diagram means that participants were randomly assigned to the two groups.
Next, the researcher must choose two levels of the independent variable, such as an experimental group that receives a treatment and a control group that does not. Thus, a researcher might study the effect of reward on motivation by offering a reward to one group of children before they play a game and offering no reward to children in the control group. A study testing the effect of a treatment method for reducing smoking could compare a group that receives the treatment with a control group that does not. Another approach would be to use two different amounts of the independent variable—that is, to use more reward in one group than the other or to compare the effects of different amounts of relaxation training designed to help people quit smoking (e.g., 1 hour of training compared with 10 hours). Another approach would be to include two qualitatively different conditions; for example, one group of test-anxious students might write about their anxiety and the other group could participate in a meditation exercise prior to a test. All of these approaches would provide a basis for comparison of the two groups. (Of course, experiments may include more than two groups; for example, we might compare two different smoking cessation treatments along with a no-treatment control group—these types of experimental designs will be described in Chapter 10).
Finally, the effect of the independent variable is measured. The same measurement procedure is used for both groups, so that comparison of the two groups is possible. Because the groups were equivalent prior to the introduction of the independent variable and there were…
