After the father finds out that Mork is from another planet, the father has hands are out in the air then puts them by his body then when the camera goes on Mork, there is a hand visible on the right hand side.
Mindy tells Mork he can set the table, but utensils and napkins are already on the table and she has cereal bowls and coffee mugs ready to go on the counter, so there is nothing to set.