More basics Confounds Randomization concerns Randomization prevents experimental bias Assignment by experimenter Counterbalancing Statistical assumptions a requirement for statistical tests of significance Why would you use the observation methodology instead of experiments?More Basics „ Confounds „ Randomization Concerns „ Randomization prevents experimental bias „ Assignment by experimenter „ Counterbalancing „ Statistical assumptions „ A requirement for statistical tests of significance „ Why would you use the observation methodology instead of experiments?