The classic experiment requires both a control and an experimental group to which subjects are randomly allocated.
Successful attacks were allocated randomly to a part of the target's body.
For this study 160 women at risk of premature delivery were randomly allocated to the trial drug or placebo (80 each).
Unless you believe that anyone randomly allocated to the vaccine group just *happens* to have healthier immune systems than people who haven't been.
Patients were randomly allocated to groups for each test substance.
For the initial experiment, at day 7, 70 mice were randomly allocated to one of three groups.
Of themselves the letters and numbers had no meaning; they appear to have been allocated randomly.
What made this trial novel was that the subjects were randomly allocated to their test groups.
Successful attacks are allocated randomly (or by decision) to a part of the target's body.
Each horse has a stall or place randomly allocated in the barrier draw for the race.