Transcribed Text
Problem 1:
An investigator is interested in the effects of stress on reaction time. She gives a reaction time test to
three groups of subjects: one group that is under a great deal of stress, one group under a moderate
amount of stress, and a third group that is under almost no stress.
The data is presented below, and also provided in the Excel spreadsheet. This data is reaction times;
therefore, a lower reaction time indicates that a subject performed better:
High
Stress
Moderate
Stress
Low
Stress
6 8 10
7 10 11
4 11 8
5 7 6
6 12 13
3 11 12
Theory A suggests that subjects under a moderate amount of stress will perform better than subjects in
either the very low or the very high stress groups.
Theory B predicts that subjects in the high stress group will perform better than subjects in either the
low stress or the moderate stress groups.
Theory C predicts that subjects in the moderate stress condition will perform significantly more poorly
than subjects in the low stress condition.
a. Using a significance level α = 0.05, perform the overall one-way ANOVA and then determine
whether the data below provide evidence that the mean reaction time differs based on the level
of stress. Provide your ANOVA table.
b. If the results from part (a) show that there is a difference in the mean reaction time for varying
stress levels, perform additional analysis to test whether Theory A, Theory B, or Theory C is
accurate or if none of them can be shown to be accurate. State your conclusion and provide the
appropriate test statistics. Again, you should use a significance α = 0.05.
Problem 2:
Everyone has heard the adage that “you can’t teach an old dog new tricks.” In an attempt to
demonstrate that it is harder to teach an old dog new tricks versus a puppy, a researcher went to the
pound and adopted 15 old dogs and 15 puppies. The researcher then attempted to teach each of the 30
dogs one of the standard dog tricks, "sit", "stay", and "roll over." The researcher taught only one trick to
each dog and keep a record of how many days it takes before they learned the tricks. The results of the
experiment are listed in the table below, and also provided in the Excel spreadsheet:
Sit Shake Roll
Over
Puppies 2 4 6
1 5 9
3 4 7
1 6 8
2 7 10
Old
Dogs
2 9 13
5 10 12
2 11 15
4 13 17
3 7 13
Based on this data, conduct a two-way analysis of variance to determine if it is more difficult for old
dogs to learn new tricks compared to puppies. Create an interaction graph as part of your solution.
These solutions may offer step-by-step problem-solving explanations or good writing examples that include modern styles of formatting and construction
of bibliographies out of text citations and references. Students may use these solutions for personal skill-building and practice.
Unethical use is strictly forbidden.