• 2022-06-01
    What are pitfalls of observational studies?
    A: It might result ethical issue
    B: it is difficult to ensure a valid counterfactual
    C: we might not think of all the control variables
    D: some variables are very hard to measure
  • B

    内容

    • 0

      It is because Chinese is very useful ______. A: that we study it very hard B: why we study it hard C: what we study it hard D: which we study it hard

    • 1

      Animals' feelings are very difficult to measure, which make the hedonistic view hard to work with on a practical level.

    • 2

      What we measure is more critical to the control process than how we measure.

    • 3

      According to some publishers, what might be the future of books like?

    • 4

      I think I might have. My wrists hurt all the time.