AP PSYCHOLOGY

Detailed explanation-1: -To implement stratified sampling, first find the total number of members in the population, and then the number of members of each stratum. For each stratum, divide the number of members by the total number in the entire population to get the percentage of the population represented by that stratum.

Detailed explanation-2: -While not necessary for simple sampling, a sampling frame used for more advanced sample techniques, such as stratified sampling, may contain additional information (such as demographic information).

Detailed explanation-3: -In stratified sampling, the population is partitioned into non-overlapping groups, called strata and a sample is selected by some design within each stratum. For example, geographical regions can be stratified into similar regions by means of some known variables such as habitat type, elevation, or soil type.

Detailed explanation-4: -In a stratified random sample design, the units in the sampling frame are first divided into groups, called strata, and a separate SRS is taken in each stratum to form the total sample. The strata are formed to keep similar units together-for example, a female stratum and a male stratum.