In an Experiment,researchers Exposed Half the Children to 2 Hours

Multiple Choice

In an experiment,researchers exposed half the children to 2 hours of violence on television every day for a month and made sure the other half saw no violence on television at all.At the end of the month,they measured the aggressiveness in the children.The fact that the researchers arranged for some children to watch violence on television and others to not is an example of:

A) matched pairs.
B) matched samples.
C) correlation.
D) manipulation.