Contents

142 PART II: Descriptive MethodsKey Conceptpopulation is often practically impossible. Therefore, researchers usually selecta subset of the population to represent the population as a whole.We need to develop a specific list of the members of the population in orderto select a subset of that population. This specific list is called a sampling frameand is, in a sense, an operational definition of the population of interest. Ina survey of students’ attitudes toward computer services, the sampling framemight be a list obtained from the registrar’s office of all currently enrolled students.The extent to which the sampling frame truly reflects the population ofinterest determines the adequacy of the sample we ultimately select. The listprovided by the registrar should provide a good sampling frame, but somestudents might be excluded, such as students who registered late.The subset of the population actually drawn from the sampling frame iscalled the sample. We might select 100 students from the registrar’s list to serveas the sample for our computer survey. How closely the attitudes of this sampleof students will represent all students’ attitudes depends critically on howthe sample is selected. Each member of the population is called an element. Theidentification and selection of elements that will make up the sample are atthe heart of all sampling techniques.It is important to emphasize at this point that samples are of little or no interestin themselves. A new computer facility is not going to be built for thesole use of the 100 students surveyed. Similarly, the social psychologist is notSTRETCHING EXERCISE IIdentifying representative samplesPresented on the left side are descriptions of four populations. Find the sample on the right side thatrepresents each population.PopulationsSamples1 60% women, 40% men A 132 women, 44 men90% ages 18–22, 10% age 22 114 ages 18–22, 62 age 2270% freshman/sophomore, 30% 141 freshman/sophomore, 35junior/seniorjunior/senior2 80% women, 20% men B 244 women, 61 men60% ages 18–22, 40% age 22 183 ages 18–22, 122 age 2270% freshman/sophomore, 30% 213 freshman/sophomore, 92junior/seniorjunior/senior3 75% women, 25% men C 48 women, 12 men65% ages 18–22, 35% age 22 54 ages 18–22, 6 age 2280% freshman/sophomore, 20% 42 freshman/sophomore, 18junior/seniorjunior/senior4 80% women, 20% men D 150 women, 100 men90% ages 18–22, 10% age 22 225 ages 18–22, 25 age 2270% freshman/sophomore, 30% 175 freshman/sophomore, 75junior/seniorjunior/seniorFrom Zechmeister, Zechmeister, & Shaughnessy, Essentials of Research Methods in Psychology, McGraw-Hill, 2001, p. 124.