A compound sentence contains two or more coordinate clauses:
The word 'and' in these sentences is a coordinating conjunction.
NOTE: The last sentence contains what appears to be a comma splice. The rule is that grammatically complete clauses should be punctuated with a semicolon, or made into separate sentences. The sentence is an example of a valid exception to the rule. The guideline for breaking the rule is that "a comma is preferable when the clauses are very short and alike in form, or when the tone of the sentence is easy and conversational" (Strunk & White, The Elements of Style).
There is room for disagreement here. What do you think?