To fill in the truth table for the proposition $q \leftrightarrow p$ (which means "q if and only if p"), we evaluate the biconditional statement. The statement $q \leftrightarrow p$ is true when both $p$ and $q$ have the same truth value, either both true or both false.

Here is the filled truth table:

\hline p & q & q \leftrightarrow p \\ \hline T & T & T \\ T & F & F \\ F & T & F \\ F & F & T \\ \hline \end{array}$$ Would you like details on how this table is derived or have any other questions? Here are 5 related questions for further practice: 1. What is the truth table for $$p \leftrightarrow \neg q$$? 2. How does $$p \rightarrow q$$ differ from $$p \leftrightarrow q$$? 3. Can you create a truth table for $$\neg(p \leftrightarrow q)$$? 4. What is the truth table for $$(p \vee q) \leftrightarrow (p \wedge q)$$? 5. How would the truth table change for $$p \leftrightarrow (q \vee \neg r)$$? **Tip:** In logical biconditional statements ($$\leftrightarrow$$), the result is true only when both components share the same truth value.