Answer to Question 1
a. Simple random samplesWhen the population is specified, we use some strategy for selecting participants without bias (e.g., each has a specified probability of being selected). It can involve random number tables, flipping a coin, or any other unbiased procedure.
b. Systematic samplesWhen the population is specified and listed, the researcher selects every nth person (e.g., every 10th, 25th, etc.) for participation
c. Stratified random samplesWhen there are subgroups of interest in the population, we may want to make sure they are included. We determine the proportion of the entire sample that should come from each subgroup and sample randomly from each one so that the proportions we desire are attained.
d. Cluster samplesWhen simple random sampling might be difficult to carry out (e.g., potential participants are spread out geographically and it would be costly to do extensive traveling), we can break down the entire population into clusters and then choose clusters randomly.
Answer to Question 2
a. Definitions ignore the fact that there are important differences among people in the same category.
b. Psychologists often assume that there is a link between race, culture, and ethnicity and behavior, even though the link has not been reliably demonstrated.
c. There are often other factors that influence behavior, but race, culture, and ethnicity are more obvious, so researchers focus inappropriately on them.
d. Scientists and professional societies (e.g., in psychology, sociology, biology, and anthropology) have not achieved consensus on the reality of these constructs.
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