What is factor analysis used for?
Summarizing a number of variables by sorting them on a smaller number of factors
Examples include grouping variables like fear, worry, stress into a subset like anxiety.
What are the two types of factor analysis?
Exploratory analysis emerges from the data, while confirmatory tests a prior division.
What is the main focus of the document regarding factor analysis?
Component analysis
It is simpler than other types of factor analysis.
In component analysis, what is the starting point?
A set of scores from a sample of subjects on several variables
The factors are summarized into a smaller set of new variables.
What is the term for variables that load highly on a particular factor?
High correlation with that factor
These variables are said to load highly on that factor.
What does Multiple Group Method (MGM) aim to verify?
Whether a proposed grouping of the variables is supported by a data set
It sums scores of standardized variables thought to belong to a particular group.
What does Principal Component Analysis (PCA) aim to find?
Factors that explain as much of the variance in the data as possible
It identifies the most significant factors affecting the data.
What is the purpose of rotating the loading matrix in PCA?
To enhance interpretability of the loadings
Rotation can be orthogonal (uncorrelated) or oblique (correlated).
What is Variance Accounted For (VAF)?
The proportion of explained variance
VAF increases by adding more factors to the analysis.
What is the difference between item-test correlation and item-rest correlation?
Item-rest correlation is always lower than item-test correlation.
What is the goal of methods like Varimax in PCA?
To create a simple pattern in the data
These methods help in making the rotation process more automatic and accurate.
What is one purpose of test construction in relation to PCA?
Detection of deviant items
Items with extremely low variance should be inspected carefully.
True or false: The measurement scale of combined items is less sensitive than that of an individual item.
FALSE
The combined items’ scale is more sensitive, reducing the influence of measurement error.