1.One possible explanation for why some birds migrate and others maintain year-r
ID: 3219418 • Letter: 1
Question
1.One possible explanation for why some birds migrate and others maintain year-round residency in a single location is intelligence. Specifically, birds with small brains relative to their body size are simply not smart enough to find food during the winter and must migrate to warmer climates where food is easily available (Sol, Lefebvre, & Rodriguez-Teijeiro, 2005). Birds with bigger brains, on the other hand, are more creative and can find food even when the weather turns harsh. Following are hypothetical data similar to the actual research results. The numbers represent relative brain size for the individual birds in each sample (the higher the number, the bigger the brain).
Non-Migrating
Short-Distance Migrants
Long-Distance Migrants
18
13
19
12
16
12
6
11
7
9
8
13
4
9
5
6
5
7
N=18
Xtot=180
X2=2150
Xbar (mean)=15
Xcol=90
s2=9.6
n=6
Xbar (mean)=9
Xcol=54
s2=6.8
n=6
Xbar (mean)=6
Xcol=36
s2=3.2
n=6
Use a one-way ANOVA with an alpha of 0.05 to determine whether there are any significant mean differences among the three different groups of birds.
Compute Tukey’s HSD post hoc test if appropriate.
Write out the results of this hypothesis test in APA style.
2.
There is some evidence that high school students justify cheating in class on the basis of poor teacher skills or low levels of teacher caring (Murdock, Miller, & Kohlhardt, 2004). Students appear to rationalize their illicit behavior based on perceptions of how their teachers view cheating. Poor teachers are thought not to know or care whether students cheat, so cheating in their classes is okay. Good teacher, on the other hand, do care and are alert to cheating, so students tend not to cheat in their classes. Following are hypothetical data similar to the actual research results. The scores represent judgments of the acceptability of cheating for the students in each sample.
Poor Teacher
Average Teacher
Good Teacher
n=6
Xbar (mean)=6
Xcol=36
s2=6
n=8
Xbar (mean)=2
Xcol=16
s2=4.71
n=10
Xbar (mean)=2
Xcol=20
s2=4.67
N=24
Xtot=72
X2total=393
Use a one-way ANOVA with an alpha of 0.05 to determine whether there are significant differences in student judgments depending on how they see their teachers.
Is it appropriate to conduct a post-hoc test in this situation? Why/why not?
If it’s appropriate to conduct a post-hoc test, is it appropriate to use Tukey’s HSD? Why/why not?
Non-Migrating
Short-Distance Migrants
Long-Distance Migrants
18
13
19
12
16
12
6
11
7
9
8
13
4
9
5
6
5
7
N=18
Xtot=180
X2=2150
Xbar (mean)=15
Xcol=90
s2=9.6
n=6
Xbar (mean)=9
Xcol=54
s2=6.8
n=6
Xbar (mean)=6
Xcol=36
s2=3.2
n=6
Explanation / Answer
(1)
(A) ANOVA:
H0: There is no difference between the treatment means; that is, m1 = m2 = m3
Ha: At least one among m1, m2 and m3 is different from the other two.
One-way ANOVA with a = 0.05
Decision Rule: Reject H0 if the p- value < 0.05
One factor ANOVA Mean n Std. Dev 10 15.0 6 3.10 Non migrating 10 9.0 6 2.61 Short distance migrants 10 6.0 6 1.79 Long distance migrants 10.0 18 4.54 Total ANOVA table Source SS df MS F p-value Treatment 252.00 2 126.000 19.29 .0001 Error 98.00 15 6.533 Total 350.00 17Related Questions
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