randomly

Definition of randomization
National Cancer Institute

randomization

(RAN-duh-mih-ZAY-shun)
In research, the process by which participants in clinical trials are assigned by chance to separate groups that are given different treatments or other interventions. Neither the researcher nor the participant chooses which treatment or intervention the participant will receive. Using chance to assign people to groups means that the effects of the treatment or intervention that participants receive can be compared more fairly.

Source: NCI Dictionary of Cancer Terms