Final answer:
The hypothesis of the converse statement to "If [hypothesis], then a dog is friendly" is "a dog is friendly." Switching the hypothesis and conclusion of the original statement formulates the converse.
Step-by-step explanation:
If the conclusion of a conditional statement is "a dog is friendly," then when forming the converse statement, the hypothesis and conclusion are switched. Therefore, the hypothesis of the converse is "a dog is friendly." It is important to understand that just because the original statement may hold true, this does not necessarily imply that the converse statement is also true. The logical structure of conditional reasoning requires careful consideration to avoid fallacies such as affirming the consequent or denying the antecedent.