In an experiment examining the effects of background noise on people’s ability to understand a verbal message, one group of participants is given a comprehension quiz after listening to a passage being read to them with no background noise. For comparison, a second group of participants is given a comprehension quiz after listening to a passage being read to them with 60 decibels of conversation as background noise. This is an example of a design.

The persians landed in the plains near athens. as their army greatly outnumbered that of the greeks, the greeks hoped to find aid from nearby sparta. a long-distance runner named pheidippides was sent from athens to sparta to request , but the spartans were not able to send more soldiers at the time. regardless, the greeks were still able to win the battle. centuries later, legend developed that a runner had been sent from the battle to athens after the greek victory. after reaching athens, the runner proclaimed, "we are victorious! " and then fell to the ground and died. this legendary story is the inspiration for the modern long-distance runs that are performed today. this passage refers to the events of which battle during the persian wars? a. battle of thermopylae b. battle of salamis c. battle of plataea d. battle of marathon