<prompt> What kind of sampling should be done when there is a small group of patients, easily available?Random samplingMultiphase samplingMultistage samplingNone of the above  <response>: Random sampling simple random sampling- It is a technique whereby each sampling unit has the same probability of being selected. - Random sampling is done, when there is a small group of patients. Multiphase sampling: - This is used to take basic data from a large sample and details from a sub-sample.Multistage sampling- The first stage is to select the groups or clusters. Then, subsamples are taken in as many subsequent stages as necessary to obtain the desired sample size. Eg: 1st stage: Choice of states within countries. 2nd stage: Choice of towns within each state.3rd stage: Choice of neighborhoods within each town.Soben Peter Essentials of preventive and community dentistry 4th edition 