I have 4 categorical variables in a dataset let $X_1$, $X_2$, $X_3$ and $Y$. Where $X_1$,$X_2$ and $Y$ is a binary random variable and $X_3$ have 3 categories.
How can I study the association of $X_1$ and $Y$ fixing/controlling $X_2$ and $X_3$?
How can I study the association of $X_2$ and $Y$ considering the four variables?
What's the better way to do that? Boxplots? Using wald.test?