<prompt> Translate the following text to EnglishKatika kesi nyingi, mtazamaji ni mtafiti mwandamizi na Margaret Mead pekee huko Samoa na Oscar Lewis huko Puerto Rico ni mifano maarufu.  <response>: In most instances, the observer is the senior investigator and the only Margaret Mead in Samoa and Oscar Lewis in Puerto Rico are famous examples. 