Swollen tonsils that are not painful or do not cause other problems do not need to be treated. Your provider may not give you antibiotics. You may be asked to come back for a checkup later. If tests show you do have strep, your doctor will give you antibiotics.
Stratified Random Sampling. Stratified random sampling is a probabilistic sampling option. The first step in stratified random sampling is to split the population into strata, i.e. sections or segments. The strata are chosen to divide a population into important categories relevant to the research interest.
Randomized Block Designs. The Randomized Block Design is research design's equivalent to stratified random sampling. Like stratified sampling, randomized block designs are constructed to reduce noise or variance in the data (see Classifying the Experimental Designs). How do they do it? They require that the researcher divide the sample into relatively homogeneous subgroups or blocks (analogous to strata in stratified sampling). Then, the experimental design you want to implement is implemented within each block or homogeneous subgroup.