<prompt> Translate the following text to EnglishKama mfano wa kuaminika kwa ajili ya uchunguzi wa kipekee, ni muhimu kuamua ni nini kinachohusika na utafiti wa kipekee, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu, na kwa nini ni muhimu.  <response>: Site selects itself in specific problem-for decisive testing, have to assume uniform system with regard to issue and so convenience sample acceptable; number of cases is usually one instance; comprehensive data for specific problem-for decisive testing, need more modeling, hypotheses, and targeting to know what to study; data analysis and collection concurrent and data feed new collection, and emphasis on ruling out alternative causes; report describes instances, presents conclusions about cause, gives evidence 