托福阅读：RESEARCH DESIGNS

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托福阅读：RESEARCH DESIGNS
In the fields of psychology and sociology, a crucial decision for researchers is which research design to use. When the subject of the study is how people change or develop over time, two designs are frequently used: the cross-sectional design and the 　　longitudinal design.
　　Cross-sectional studies look at a cross-section of subjects and compare their responses. The essential characteristics ofthe design are that it includes groups of subjects at different age levels, and t:hat each subject is tested or interviewed only once. For example, researchers may give a memory test to adults in their twenties through seventies, select the youngest group as a standard, and then compare each older group to that norm.
　　Cross-sectional studies are relatively quick to do and can provide information about possible age differences. However, they do not reveal anything about individual change over time, since each subject is tested only once.
　　Longitudinal studies differ from cross-sectional studies because they test or interview the same subjects over time and therefore allow us to look at consistency or change within the same individual. The typical procedure is to select a relatively small group of subjects who are all about the same age at the beginning ofthe study and then look at them repeatedly over a period of time. Short-term longitudinal studies cover several years and　are common in research on both children and adults. Long-term longitudinal studies follow subjects rom childhood into adulthood, from early to middle adulthood, or from middle adulthood to old age. One advantage oflongitudinal studies is that any changes found are real changes, not just age-group differences.
( {/ d( Y4 v- K# |　　Select the appropriate sentences from the answer choices and match them to the research design that thev describe. TWO of the answer choices will NOT be used. This question is worth 3 points: Answer Choices
　　A group of subjects of the same age　is tested repeatedly over a long period.
　　Researchers examine an existing relationship between two groups of subjects.wｗw.ExamＷ.CoM
　　This design allows researchers to study human behavior indirectly.
　　Researchers test or interview each subject　only one time.
　　This type of study may reveal differences that are not just age-group difFerences.
8 e0 q- f% m! F　　Researchers can study consistency or change within the same individual.
' j/ W* ~  f. }; o9 m8 T0 L' {1 M　　This design can tell us about possibie differences among various age groups.