Which of the Following Factors Was NOT Necessary to Ensure

Multiple Choice

Which of the following factors was NOT necessary to ensure the internal validity of the Latané and Darley "seizure" study described in the text?

A) They made sure their conditions varied on only the key variable.
B) They made sure that the seizure overheard by participants was identical for everyone.
C) They randomly assigned participants to groups or conditions.
D) They asked participants about their knowledge of epilepsy before beginning the experiment.