<prompt> Randomization is best done byLottery systemComputer systemRandom number tablesAll of the above  <response>: C. i.e. Random number table 77 - Park 19th 78- Park 20thRANDOMIZATION - is a statistical procedure by which the participants are allocated into groups usually called Study and Control groups, to receive or not to receive an experimental preventive or therapeutic procedure, manoeuvre or intervention Randomization is an attempt to eliminate bias and allow for comparability Randomization is done only after the participant has entered the study, that is after having been qualified for the trial and has given his informed consent to participate in the study Randomization is best done by using a table of random numbers The major purpose of randomization clinical trials is to reduce selection bias in allocation of treatmentBasic step in Conducting a Randomized Controlled Trialsa Drawing up a protocold Manipulation or Interventionb Selecting reference and experimental populatione Follow upc Randomizationf Assessment of outcomeRandomization methods1. Simple randomization2. Block randomization3. Randomization based on prognostic factors4. Based on odd or even numbers - Least useful because leads to biasIn a controlled trial to compare two treatments. The main purpose of randomization is to ensure that - The two groups will be similar in prognostic factors 