If the two pandas have a cub, the new contract states the Memphis Zoo does not have to pay China a yearly fee on that. However, the cub will have to be returned to China after four years.
Panel study. A panel study is a longitudinal study design where a cross-sectional sample of units is selected and surveyed at usually regular intervals. The observation units may be individuals, households, firms or other organisations, or even countries. Household panel surveys are an important sub-type of panel study.
What is a panel? A panel is a group of people who have agreed to take part in survey research by answering questions. Research panels have existed for over a century: first as groups of people interviewed in person, then later as large panels that filled out postal mail questionnaires for companies.