In an experiment, participants were divided into various groups, and their concentration ability was measured. Firstly, half the sample was tested in the morning, and half was tested in the evening. Secondly, half the sample was tested in bright light, and half was tested in dim light. Lastly, one third of the sample was tested in silence, one third was tested while listening to popular music, and one third was tested while listening to classical music. How many conditions are there