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EXCEL |
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One-Way ANOVA |
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Perform a One-Way ANOVA Analysis: |
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Assumptions: |
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1. The populations are normally distributed. |
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2. The populations have equal standard deviations. |
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3. The samples are select independently. |
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The following are the travel times in minutes of ambulances for 3 different routes. |
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A |
B |
C |
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1 |
Route 1 |
Route 2 |
Route 3 |
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2 |
2.1 |
1.8 |
2.4 |
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3 |
2.2 |
2 |
2.1 |
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4 |
1.9 |
2.1 |
2 |
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5 |
1.8 |
2.2 |
2 |
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6 |
2 |
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1.9 |
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Enter the data; place the travel times for Route 1 in column A, Route 2 in column B |
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and Route 3 in column C. |
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Compare the travel times of the three different routes: |
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Perform a ANOVA test at the 5% significance level to determine if there exists a |
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significant difference between the travel times of the different routes. |
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Perform One-Way ANOVA Test with EXCEL: |
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1. Enter the data into columns A, B and C. |
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2. Select Tools and Data Analysis. |
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3. Select ANOVA: Single Factor and click OK. |
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4. Input the following in the dialog box: |
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a. Input Range: A1:C6. |
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b. Click on Labels (since you included the labels in your input range). |
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c. Alpha: 0.05. |
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d. Check Output Range and specify the range, if you would like the output on the same |
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spreadsheet. Output Range is A10. Choose a New Work Sheet Ply if you like a |
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new sheet. |
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e. Click OK and you will see the output below. |
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Anova: Single Factor |
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SUMMARY |
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Groups |
Count |
Sum |
Average |
Variance |
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Route 1 |
5 |
10 |
2 |
0.025 |
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Route 2 |
4 |
8.1 |
2.025 |
0.029167 |
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Route 3 |
5 |
10.4 |
2.08 |
0.037 |
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ANOVA |
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Source of Variation |
SS |
df |
MS |
F |
P-value |
F crit |
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Between Groups |
0.016642857 |
2 |
0.00832143 |
0.272834 |
0.766223 |
3.982308 |
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Within Groups |
0.3355 |
11 |
0.0305 |
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Total |
0.352142857 |
13 |
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Interpret Your Results: |
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1. State Hypothesis: |
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H0: μ1 = μ2 = μ3 |
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HA: At least one of the mean travel times are not equal. |
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2. Level of Significance: α = 0.05. |
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3. Determine Test Statistic: F = .272834 |
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4. Decision Rule: Critical F-Value: Reject Ho if F2,11 > 3.982. |
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Degrees of freedom in the numerator is k - 1 = 3 - 1 = 2 |
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Degrees of freedom in the denominator is n - k = 14 - 3 = 11 |
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5. Make a Decision: Do not reject Ho since F= .2728 does fall into the rejection region. |
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6. Conclusion: There is not enough evidence at the 5% significance level to conclude |
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that there is a significant difference in the travel times of the ambulances on the three |
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different routes. |
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© copyright 2004 Elisabeth Knowlton