colleagues. The researchers asked whether a dog wags its tail in a preferred
direction in response to positive stimuli and in another direction in response to
negative stimuli. To answer their question, they recruited 30 dogs that were family
pets. Filming each dog from above, they allowed it to view (through a slat in its cage)
three positive stimuli separately, in order of descending positivity: its owner, an
unfamiliar human, and a cat. All the dogs responded by wagging their tails to the
right. But when the dogs were presented with an unfamiliar, aggressive dog, a
negative stimulus, all dogs wagged their tails to the left.
Reference: Ref 7-1

(Study Description: Tail Wagging) Which statement is the null hypothesis for this
study?

Question 20
5 out of 5 points
A hypothesis test is said to be _____ when it produces fairly accurate results, even
when some of the assumptions underlying the hypothesis test are violated.

Question 1
5 out of 5 points
Under what conditions is it permissible to proceed with a hypothesis test even
though the assumption that the population distribution is approximately normal is
violated?

Question 2
5 out of 5 points
The null hypothesis states that:
Selected Answer:
there are no differences between the populations being studied.
Answers:
the sample being studied is different from the population from which it was drawn.
nothing exists.

a difference exists between the populations being studied.
there are no differences between the populations being studied.
Question 3
0 out of 5 points
If the percentage of scores falling between the mean and a z score of 0.50 is 19.15,
then what is the percentage of scores falling below a z score of –0.50?

Question 4
5 out of 5 points
Study Description: Dance Dance Revolution
Unnithan, Houser, and Fernhall (2006) were interested in whether playing the game
Dance Dance Revolution (DDR) affected the heart rate of overweight adolescents
differently than it affected non-overweight adolescents. Twenty-two adolescents, 10
classified as overweight and 12 as not overweight, played DDR for 12 minutes, while
the researchers measured each participant's heart rate. On average, the researchers