esearchers from Otago's Department of Psychology conducted a study to test the effects of Kiwifruit or Vitamin C tablets on vitality in adults with low Vitamin C levels.

"Participants were batch randomized so that everyone attending the clinic on the same day would receive either kiwifruit or tablets. This was done to avoid participants being exposed to the other conditions (e.g., participants seeing others receiving kiwifruit when they received tablets or vice versa). Research assistants and participants were not exposed to their tablet condition. Condition information (Vitamin C tablets vs. placebo tablets) was kept in an electronic password protected document that only the research lead had access to." (Conner et al., 2020, p. 3)

Which of the following methods were used to control bias? (choose one or more)

Group of answer choices

randomization

strict definitions

matching

restriction

blinding