I have studied several forms of comedy as a hobby for many years. It's not an exact science by any stretch, and in the end all you can do is know what makes you laugh and what you personally find funny. There is so much intangible in the form of "comedy". Laughing is an unnatural act. Literally, laughing resembles a seizure and makes your body react in a form of involuntary convulsion – but in a good way. Making people laugh is probably one of the hardest things you can attempt to do, especially as a stand up comedian where all you have is your words, or in the case of Carrot Top, cheap props, which is why he's not the most respected comedian because he can't do his act without the crutches. Most stand ups are armed with words and wit, which feels kind of naked on a stage.
Making a comedic film is not easy either, but you have tools and things that you can use, so it's more comforting. Sitting in an audience, lights dimmed and the flickering images and sounds emanating represent the truest test of a comedy film. Luckily, I have been in the audience when my own alleged comedies have succeeded and failed to cause the desired reaction of laughing. You learn a lot from the experience of being in a room full of strangers and as a filmmaker you attempt to manipulate the audience into the communal response. What bombs with one audience, may work well with another group of people. Sooner or later you just have to form your own opinion of what is funny and go with that, not worrying whether it plays in Peoria. Be true to your own sense of humor and be content if you find it funny.