Patty wants to see what kind of light bulbs last longer. She sets up two lamps. One lamp has an incandescent light bulb, and the other lamp has a fluorescent light bulb. She turns them on at the same time and leaves them on until they burn out. The incandescent bulb took 83 days and the fluorescent bulb took 417 days to burn out. What is the independent variable and dependent variable in patty’s experiment?