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What are the sources of variance in a one-way ANOVA?
between-groups variance and within-groups variance.
What does the total sum of squares represent?
the total variability in the data.
What test is used to assess heterogeneity of variance?
Levene's test
How many degrees of freedom are associated with the between-groups variance in a one-way ANOVA?
k - 1, where k is the number of groups.
What values are used to calculate the F statistic?
the ratio of the mean square between-groups to the mean square within-groups.
What are the three questions that can be asked of the data in a two-way design?
Are there main effects for each independent variable?
Is there an interaction effect between the independent variables?
How do these effects influence the dependent variable?
If there is interaction between two variables, what will their relationship look like on a graph?
the lines representing the relationship between the variables will cross or diverge in a non-parallel manner.
What is the purpose of a multiple comparison test?
to determine which specific groups differ from one another following an ANOVA.
What is the difference between a per comparison error rate and a familywise error rate?
The per comparison error rate refers to the probability of a Type I error for an individual comparison, while the familywise error rate refers to the probability of making at least one Type I error across all comparisons.
What is the difference between post hoc multiple comparisons and planned comparisons?
Post hoc comparisons are conducted after observing significant results to identify differences between specific groups, while planned comparisons are specified before the analysis and focus on specific hypotheses.
What is a minimum significant difference (MSD)?
the smallest difference between group means that is considered statistically significant.
Which multiple comparisons tests are considered most conservative and which are considered most liberal?
Scheffé's test is considered conservative, whereas Fisher's Least Significant Difference (LSD) test is considered liberal.
What is a simple effect in a factorial design?
the effect of one independent variable at a specific level of another independent variable.
What are the nonparametric analogs of t and ANOVA for independent and repeated measures?
independent samples t-test is the Mann-Whitney U test, and for ANOVA it is the Kruskal-Wallis test; for repeated measures, the Wilcoxon signed-rank test is used.
What are the reasons you would choose to use a nonparametric test to analyze data?
when data does not meet assumptions of normality, homogeneity of variance, or when data are ordinal.
What tests can be used to determine if data follow a normal distribution?
Shapiro-Wilk test and the Kolmogorov-Smirnov test
What is the purpose of the chi-square test?
assesses whether there is a significant association between categorical variables.
What are two assumptions of data for use with chi-square?
The observations should be independent.
The expected frequency in each category should be 5 or more.
What is the purpose of a goodness-of-fit test?
determines how well an observed frequency distribution fits an expected distribution.
What is a standardized residual in chi-square and how is it interpreted?
the difference between observed and expected frequencies, standardized by the expected frequency; it helps assess which categories contribute most to the chi-square statistic.
What is a test of independence with chi-square?
assesses whether two categorical variables are related or independent of each other.
What kind of table is used to present data for a test of independence?
A contingency table
What are the degrees of freedom associated with a test of independence?
(number of rows - 1) * (number of columns - 1).
How does a scatterplot reflect large and small correlations?
A scatterplot reflects large correlations with points clustering closely along a straight line, while small correlations display points more widely dispersed.
What is the range of scores for a relative reliability coefficient?
-1 to 1.
What does a reliability coefficient of -.89 tell you about the relationship between X and Y?
a strong negative relationship between X and Y.
What is the effect size index for the Pearson correlation?
square of the correlation coefficient (r²).
What statistics can be used to determine the correlation of two ordinal scores?
The Spearman rank correlation coefficient
What is the purpose of regression analysis?
to predict the value of a dependent variable based on the value(s) of one or more independent variables.
What is the coefficient of determination? What does it mean?
(r²) indicates the proportion of variance in the dependent variable explained by the independent variable(s).
What is the equation for the regression line, and what does each term mean?
Y = a + bX; 'Y' is the predicted value, 'a' is the y-intercept, 'b' is the slope (change in Y for each unit change in X), and 'X' is the independent variable.
What does the regression line represent?
the best fit line that predicts the dependent variable based on the independent variable.
What is a residual in regression analysis?
the difference between the observed value and the predicted value in a regression analysis.
What value is used to represent the prediction accuracy in a multiple regression equation?
R² (coefficient of determination).
How are beta weights used?
to indicate the strength and direction of the relationship between each independent variable and the dependent variable in a regression analysis.
Why is collinearity a problem when interpreting a multiple regression procedure?
Collinearity can lead to unstable estimates of regression coefficients, making it difficult to determine the individual effect of each independent variable.
What is a dummy variable?
a numerical variable used in regression analysis to represent subgroups of the sample; it takes on values of 0 or 1 to indicate the presence or absence of a category.
How does logistic regression differ from linear regression?
Logistic regression is used when the dependent variable is categorical, whereas linear regression is used when the dependent variable is continuous.
How do the outcome categories in logistic regression represent?
The probability of a specific outcome occurring based on the independent variables.
What is an odds ratio?
the odds of an outcome occurring in one group relative to the odds of it occurring in another group.
