Deck 7: Selecting an Appropriate Method

Question 1

Those who play the card game Poker try to hide the quality of their hand. This is the
basis for the term, "poker face" -- indicating that the player successfully conceals how
good a poker hand he or she has. But can the quality of a hand be seen from other
behavior? Researchers prepared 20 video clips of players placing a bet in the World
Series of Poker tournament. Seventy-eight college students viewed the clips and
rated the quality of the poker hand based on behaviors of the players. The students
were randomly assigned to three groups. None of the students knew how to play
poker. One group was shown video clips that were of the player's head only, another
group was shown video clips that were of the player's upper body only, and the third
group was shown video clips that were of the player's arm movement only.
The correlations between the quality of the poker hand and the student rating were
near zero for the upper body and face only videos, but the correlation between the
student rating and the quality of poker hand was relatively large and positive for the
arm movement only videos. The researchers concluded that arm movement cues
were better indicators of the quality of the poker hands of experienced poker players
than head or upper body movements. (Perhaps they need to develop "poker arms!")

Answer 1

Question 2

The black woodpecker is the second largest woodpecker species in the world and
therefore it must nest in large trees. To see whether modern forestry practices (clear
cutting) pose a threat to the black woodpecker, investigators studied the nest-site
selection in a large forest. The investigators used radio telemetry to monitor 219
birds to see where they built nests. The investigators used the data to estimate the
proportion of woodpecker nests that were in clear cut areas.

Answer 2

Question 3

Political advertisements on television are very frequent in election years. These
political ads boost citizens' involvement, their interest in the election, and awareness
of current issues. In recent years, candidates' advertising seems to focus on
criticizing and discrediting their opponents rather than promoting their own ideas and
solutions to problems. Is it possible that positive and negative advertising alters voter
participation?
During a recent electoral cycle, investigators randomly assigned California voters to
one of two groups. The voters in one group were shown a "positive" 30-second
advertisement about candidates that were actually running for office. Another group
of voters was shown a 30-second negative ad. After the ads were shown, the voters
were asked about their voting intentions and general level of involvement in the
campaign. Sixty-four percent of those who watched a positive ad intended to vote.
Fifty-eight percent of those exposed to the negative versions of the campaign said
they were likely to vote. The researchers concluded that the proportion of people who
intend to vote was significantly lower for those who see a negative ad.

Answer 3

For each of the studies below, answer the four key questions:

Question 4

In some dogs, tail-chasing is a repetitive behavior that is expressed as circling with the
dog's attention directed towards its tail. Tail-chasing is reported more frequently in
certain dog breeds, and some veterinarians believe this behavior may have a genetic
basis. It is also possible that there re biochemical factors leading to the behavior. In
a clinical study, 15 dogs of various breeds exhibiting tail-chasing behavior were
identified.
After a fasting period of 12 to 16 hours, blood samples were taken from each dog and
total cholesterol was measured. Blood samples were also taken from fifteen dogs that
did not exhibit tail-chasing behavior. Tail chasing dogs had significantly higher mean
total cholesterol than dogs who did not chase their tails.