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Questions about multivariate analyses

  1. What is heterogeneity of variance in SPSS Probit and Logit procedures?

  2. How do I test whether one independent variable has an influence on a dependent variable other than via the mediation of a second independent variable? (Sobel Test)

  3. What is collinearity in multiple regression, and what do I do about it?

  4. How do I find the condition number of a matrix using R?

  5. Is there an optimal ratio of cases to predictor variables I should have before performing a multivariate analysis or any guide as to total sample size?

  6. Which matrix of loadings do I use doing a principal components extraction or non-PC analysis with a direct oblimin rotation when doing a factor analysis?

  7. A guide to the pros and cons of choosing a method for producing factor scores from a factor analysis

  8. What thresholds should I use for factor loading cut-offs?

  9. How do I compare a pair of factor loadings?

  10. What is the difference between principal components analysis, principal axis analysis and other factor extraction methods?

  11. How many factors should I retain in a factor analysis?

  12. A note on Cronbach's Alpha.

  13. How do I interpret variables which load on more than one factor?

  14. What is multidimensional scaling and how do I do it?

  15. What is canonical correlation and where can I use it?

  16. When should I use a Multivariate Analysis of Variance (MANOVA)?

  17. Why are the standard errors so large in logistic regression?

  18. How do I choose between different logistic regression models?

  19. How do I perform a cluster analysis in R?

  20. Which discriminant analysis should I use to obtain thresholds to indicate levels of abnormality using a single variable?

  21. How do I assess the importance of variables in a Normal Discriminant analysis?

  22. Can you recommend any two group discriminant diagnostics?

  23. Which output criteria should I use when using the casewise results option with the Normal discriminant method in SPSS?

  24. How do I plot and interpret a ROC curve in assessing strength in two group prediction?

  25. How do I handle missing data in multivariate analyses in SPSS?

  26. Using SPSS syntax to impute last observation carried forward (LOCF) for missing values in SPSS

  27. How do I find complete cases in SPSS and R?

  28. How can I detect identical (duplicate) cases in SPSS without having an ID number?

  29. What is Euclidean distance and how do I compute it?

  30. How do I detect multivariate outliers?

  31. Structural equation modelling in R

  32. Can you recommend any statistical textbooks?

  33. How do I check for multivariate normality?

  34. What do I do if I have unequal group covariance matrices when doing a MANOVA?