Match each example of a study to the type of method used. researchers develop a survey and ask the same questions to 40,000 randomly selected people. researchers interview or survey the same 1,000 families every 5 years over a 40-year period. researchers conduct long interviews with open-ended questions with 40 couples. researchers observed 15 families in their homes over a period of 1 year. researchers survey family members on how many hours per week they spend doing various tasks or ask them to keep a diary of what they do every 30 minutes over an entire day over a period of a week.