Useful tips for everyday
How do you calculate to total correlation? Subtract the score for the first item from the total for each person. Correlate the scores on the…
What does a factor analysis measure? Factor analysis is a statistical method used to describe variability among observed, correlated variables in terms of a potentially…
How to choose variables for multivariable Cox model? Assume there are three independent variable as follows: I want first conduct univariable analysis for each variables…
How do you interpret a Cox proportional hazard model? If the hazard ratio is less than 1, then the predictor is protective (i.e., associated with…
How do you interpret chi-square results in Excel? The symbol of the chi-square test is “x2” (i.e., “x” raised to the power 2). If the…
How is the probit model used in data analysis? In the probit model, the inverse standard normal distribution of the probability is modeled as a…
Why do we need to normalize data before PCA? Normalization is important in PCA since it is a variance maximizing exercise. It projects your original…
What is a nested Anova? A nested ANOVA (also called a hierarchical ANOVA) is an extension of a simple ANOVA for experiments where each group…
When to use a GAM instead of a GLM? Someone recently told me that GAMs should only be used when I assume the data structure…
What is the problem with repeated measures? Repeated measures designs have some disadvantages compared to designs that have independent groups. The biggest drawbacks are known…