A city in California has asked Professor Rodriguez to conduct an experiment on earthquake preparedness. Professor Rodriguez will assess the preparedness of a random sample of residents in the city and the city will mail out their annual brochure on earthquake safety. Then, 2 weeks later, he will again assess the preparedness of those residents. Right after the brochures are mailed, a large earthquake is reported in Japan. Which threat to internal validity does this pose?a. selection.
b. testing.
c. history.
d. maturation.


Respuesta :

Answer:

c. history.

Explanation:

Internal validity is defined as the degree of confidence that the results of the experiment are properly interpreted and valid. Faced with a threat to internal validity, the researcher resorts to the History of external events that occur during the experiment and do the alternative modifications.