Identify two threats to external validity and their subgroups. ...

[faduma]

Identify two threats to external validity and their subgroups.
 
  What will be an ideal response?

Question 2

The initial victim surveys discovered only about half as much crime as appeared in official statistics.
 
  Indicate whether the statement is true or false

[smrerig]

Answer to Question 1

Students should identify and explain:
A) Population Validity - Some findings may not be generalizable to all members of a population. Therefore, many experiments suffer from low external validity.
B) Reactivity - a general threat to external validity that arises because subjects are aware that they are in an experiment and being studied.
1) Hawthorne Effect - a reactivity named after a famous case in which subjects responded to the fact that they were in an experiment more than to the treatment.
2) Demand Characteristics - a type of reactivity in which the subjects in experimental research pick up clues about the hypothesis and alter their behavior accordingly.
3) Placebo Effect - when subjects do not receive the real treatment and instead receive a placebo or imitation treatment but respond as though they have received the real treatment.
4) Each of these types of reactivity threaten the ability of the researcher to generalize the results of a study across various settings.

Answer to Question 2

F