A researcher wants to test whether viewing television violen…

A researcher wants to test whether viewing television violence increases aggressive behavior. He allows his participants to choose whether they would prefer to view a violent or a nonviolent film. He then subsequently records the number of aggressive behaviors they show in a competitive game. The researcher cannot legitimately make a causal statement based on his findings, because his study:

Nielsen Media Firms uses its “TV boxes” to record families’…

Nielsen Media Firms uses its “TV boxes” to record families’ TV habits. Every year, they report the average number of hours families spend watching TV. The most recent report showed that families watch an average of five hours and four minutes of TV per day. This is an example of: