A statistics instructor wonders whether there is a significant difference in her student's GPA for each of her three sections. She randomly selects the GPA's from different students in each section. The data is shown below. At the 5% significance level is there evidence of a difference GPA's by section? The variance for Section 1 is .257, Section 2 is .0897 and Section 3 is .063. You must show/attach all your work to receive points.
GPA |
Section 1 |
Section 2 |
Section 3 |
3.2 |
3.0 |
2.5 |
2.7 |
3.6 |
2.9 |
2.3 |
3.4 |
2.9 |
3.4 |
3.6 |
3.2 |
3.5 |
2.9 |
2.8 |
|
3.4 |
|
a) State H0 and H1.
b) Fill in the table. All work supporting the information in the table must be included on this sheet or attached.
Source of Variation |
Degree of Freedom |
Sum of Squares |
Mean Square |
F |
Treatment |
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|
--------- |
--------- |
--------- |
Error |
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|
--------- |
--------- |
|
Total |
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|
--------- |
|
|
c) Determine the upper-tail critical value from the F-distribution.
d) What is your decision? Reject or do not reject Ho?
e) What is your conclusion?