This problem demonstrates a possible (though rare) situation that can occur with group comparisons.  The groups are sections and the dependent variable is an exam score.
Section 1Section 2Section 3
6754.955.6
76.457.365.6
52.35057.3
60.149.166.4
5975.673
62.17263.8
72.735.967
70.733.370.5
67.960.162.5
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Run a one-factor ANOVA (fixed effect) with α=0.05\displaystyle \alpha={0.05}.  Report the F-ratio to 3 decimal places and the P-value to 4 decimal places.
F=\displaystyle {F}=
p=\displaystyle {p}=
What is the conclusion from the ANOVA?


Calculate the group means for each section:
Section 1:  M1=\displaystyle {M}_{{1}}=
Section 2:  M2=\displaystyle {M}_{{2}}=
Section 3:  M3=\displaystyle {M}_{{3}}=
Report means accurate to 2 decimal places.

Conduct 3 independent sample t-tests for each possible pair of sections.  (Though we will see later that it might not be appropriate, retain the significance level α=0.05\displaystyle \alpha={0.05}.)  Report the P-value (accurate to 4 decimal places) for each pairwise comparison.
Compare sections 1 & 2:  p=\displaystyle {p}=
Compare sections 1 & 3:  p=\displaystyle {p}=
Compare sections 2 & 3:  p=\displaystyle {p}=
Based on these comparisons, which pair of groups have statistically significantly different means?


Thought for reflection:  What do the results of the pairwise comparisons suggest about the original conclusion from the ANOVA?