A major threat to the internal validity (esp. time-related threats and order effects) for pre-post designs can occur as it is impossible to
a. randomly assign participants.
b. counterbalance the order of treatments.
c. control for differential effects.
d. generalize the results.

Attitudes toward homeless people. negative attitudes toward poor people are negative when a person is homeless? to find out, a common. are attitudes more description of a poor person is read to subjects. there are two versions of this description. one begins jim is a 30-year-old single man he is currently living in a small single-room apartment the other description begins jim is a 30-year-old single man. he is currently homeless and lives in a shelter for homeless people. otherwise, the descriptions are the same. after reading the description, you ask subjects what they believe about jim and what they think should be done to 26 him. the subjects are 544 adults interviewed by telephone. outline the design of this experiment.