PSYC*2360 Chapter 9: Multigroup Design Flashcards
What is it called when a participant in a study actively attempts to identify the purpose of the research?
Hypothesis-guessing
Which term refers to a study’s ability to find differences between groups when there is a real difference (the probability that a study will yield significant results)?
Power
What is an easy way to increase the power of a study?
Increase the strength of the manipulation
What is a confound?
A variable that the researcher unintentionally varies along with manipulation
What is methodological pluralism?
The use of multiple methods or strategies to answer a research question
What is a multigroup design?
An experimental design with three or more groups
What are three advantages of multigroup designs?
- More efficient (rather than conducting several separate two-group studies, one multigroup study can be run)
- Can identify nonlinear relationships
- Help address potential alternative explanations
T or F: having more than two groups or levels of the IV allows for the identification of potential nonlinear relationships.
True
What are nonlinear relationships?
Any association between variables that the use of just two comparison groups cannot uncover
How are nonlinear relationships often identified on a graph?
As a curved or curvilinear line
What is the difference between an empty control group and a placebo group?
- Empty control: A group that doesn’t receive any form of treatment and just completes the dependent variable
- Placebo: A group where participants falsely believe they are getting treatment
Which type of control group shows how participants respond under normal conditions?
An empty control group
Which type of control group allows for an evaluation of how much participants’ responses on the DV are due to expectations about the potential effects of the IV?
The placebo group
What are placebo groups also known as?
Expectancy groups
Under what conditions is a one-way ANOVA the appropriate statistical analysis?
When the IV has three or more levels and the DV is measure on a continuous scale
What does a one-way ANOVA determine?
Whether responses from different conditions are essentially the same or if the responses from at least one of the conditions differs from the others
When conducting a one-way ANOVA, what are assumed to be the two sources of variance?
- Variance between subjects
- Variance within subjects
In a one-way ANOVA, by subtracting the mean of each participant’s group from the grand mean, squaring those differences, then adding up the squared difference, what is being calculated?
The between SS
In a one-way ANOVA, by subtracting each participant’s score from the mean of their group, squaring the difference, then adding up the squared differences, what is being calculated?
The within SS
How is effect size calculated in a one-way ANOVA?
By dividing the between SS by the total SS
In a one-way ANOVA, if the variance between groups is simply due to error, will the within SS and between SS be the same or different values?
The same
In a one-way ANOVA, if the variance between groups is due to the treatment, will the within SS and between SS be the same or different values?
Different
When stating the results from a one-way ANOVA, which two values go in parentheses after the F before the equal sign (F (X, Y)=)?
X= Between-subjects degrees of freedom
Y= Within-subjects degrees of freedom
What is the notation for calculated effect size when reporting a one-way ANOVA?
eta^2
T or F: ANOVAs not only indicate whether there is any difference among levels of the IV, but they also locate any differences that are present.
False. Indicate whether there is any difference among levels of the IV, but do NOT locate any differences that are present.
To test for specific differences when using ANOVAs, what type of analysis is often used?
Exploratory analyses
What are exploratory analyses?
Statistical tests that examine potential differences that were not anticipated or predicted prior to conducting the study
In the context of a one-way ANOVA, which type of exploratory analyses can be used?
Post-hoc tests
What are post-hoc tests?
Statistical tests that examine all possible combinations of conditions in a way that statistically accounts for the fact that not all of them were predicted ahead of time
The Tukey HSD test is an example of which type of statistical analysis?
A post-hoc test
What are planned contrasts?
Statistical tests that examine comparisons between groups that were predicted ahead of time
Although planned contrasts are similar to t-tests, what do they correct for that t-tests don’t?
Correct for the number of comparisons
Do planned contrasts control for the probability of type 1 or type 2 errors?
Type 1
What is an added benefit of planned contrasts?
They allow for the comparison of combined conditions to other conditions in the study
What does a chi-square test of independence examine?
Whether the distribution of participants across categories is different from what would happen if there were no difference between groups
In a chi-square test of independence, what would need to happen for there to be a significant difference?
There would need to be more participants than expected in some conditions compared to others
In a chi-square test of independence, both variables must be what type?
Categorical
T or F: A chi-square test of independence is a frequency measure.
True
What is the chi-square symbol?
X^2
How are degrees of freedom calculated for a chi-square test?
df= (number of rows-1)(number of columns-1)
When reporting the results from a chi-square test, what does Φ represent?
Calculated effect size
K. Pearson is often associated with correlation, but he also developed which method of statistical analysis?
The chi-square test
W. S. Gosset developed which method of statistical analysis?
The t-test
R. A. Fisher developed which method of statistical analysis?
The ANOVA (F-test)
