A researcher is looking at the effect of drinking alcohol on the ability to play darts. He recruits 20 dart players from the nearby pub and has them come to a lab where he flips a coin for each player. If the coin comes up heads, he has the player drink a pint of beer. If the coin comes up tails, he has the player drink a pint of soda. Each player then throws three darts at a dartboard and the score is recorded. The researcher calculates that the soda-drinkers score, on average, 2.5 points more than the beer-drinkers.

The paragraph above describes a/an _____________.The participants who drink beer are th_____________, the participants who drink soda are the _____________. Flipping a coin to decide which player gets which drink is an example of _____________.

Choose from the list below to fill in the blanks.

a. treatment group
b. control group
c. controlled experiment
d. observational study
e. placebo
f. confounding factor
g. randomization