.. In each of the following examples,, identify the sampling method being used and justify your answer .

a)) A sample of 2,000 students was chosen to estimate the average grade in Arabic of the sixth grade students in Cairo public schools.. The average six th grade enrollment in Cairo elementary schools is 10 0 0 00 students.. Thus,, 20 sc hools were randomly selected and within each of those schools all six th graders were tested..

b)) Instructors teaching Statistical methods are interested in knowing what study techniques their students are utilizing.. Instead of asking all students,, the researc hers randomly select 20 students from each of the sections to comprise their sample..

c)) Choosing three students from a class to receive chocolate by putting all the students'' names in a bowl and picking out three names randomly..

d)) D ividing a major into four groups ( f reshman,, sophomore,, junior and senior)) and take a random sample from each group..