Practice Problems: ANOVA
A researcher is concerned about the level of knowledge possessed by university students regarding United States history. Students completed a high school senior level standardized U.S. history exam. Major for students was also recorded. Data in terms of percent correct is recorded below for 32 students. Compute the appropriate test for the data provided below.
Education | Business/Management | Behavioral/Social Science | Fine Arts |
62 | 72 | 42 | 80 |
81 | 49 | 52 | 57 |
75 | 63 | 31 | 87 |
58 | 68 | 80 | 64 |
67 | 39 | 22 | 28 |
48 | 79 | 71 | 29 |
26 | 40 | 68 | 62 |
36 | 15 | 76 | 45 |
Source | SS | df | MS | F |
Between | 63.25 | 3 | 21.0833333333 | .04 |
Within | 12298.25 | 28 | 439.2232143 | |
Total | 12361.5 | 31 | | |
- What is your computed answer? F = .04 (3,28), not significant
- What would be the null hypothesis in this study? There will be no difference in history test scores between students with different academic major.
- What would be the alternate hypothesis? There will be a difference somewhere in history scores between the four groups with different academic major.
- What probability level did you choose and why? p = .05 There is little risk involved if either a Type I or a Type II major is made.
- What were your degrees of freedom? 3, 28
- Is there a significant difference between the four testing conditions? No significant differences were found between the four groups in terms of performance on a U.S. history exam.
- Interpret your answer. Students regardless of academic major performed equally (in this case poorly) on a high school senior standardized U.S. history exam.
- If you have made an error, would it be a Type I or a Type II error? Explain your answer. If I have made an error, it would be a Type II error. There really is a difference in history knowledge between academic major but somehow I failed to demonstrate that with this study.
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