In: Statistics and Probability
The following data are from an experiment designed to investigate the perception of corporate ethical values among individuals who are in marketing. Three groups are considered: management, research and advertising (higher scores indicate higher ethical values).
Marketing Managers | Marketing Research | Advertising |
9 | 7 | 5 |
8 | 7 | 6 |
7 | 6 | 5 |
8 | 6 | 4 |
9 | 7 | 5 |
7 | 6 | 5 |
Sum of Squares, Treatment | |
Sum of Squares, Error | |
Mean Squares, Treatment | |
Mean Squares, Error |
Difference | Absolute Value | Conclusion |
1 - 2 | SelectSignificant differenceNo significant difference | |
1 - 3 | SelectSignificant differenceNo significant difference | |
2 - 3 | SelectSignificant differenceNo significant difference |
using minitab>stat>Anova>one way anova
we have
One-way ANOVA: Marketing Managers, Marketing Research, Advertising
Method
Null hypothesis All means are equal
Alternative hypothesis At least one mean is different
Significance level α = 0.05
Equal variances were assumed for the analysis.
Factor Information
Factor Levels Values
Factor 3 Marketing Managers, Marketing Research, Advertising
Analysis of Variance
Source DF Adj SS Adj MS F-Value P-Value
treatment 2 27.000 13.5000 27.00 0.000
Error 15 7.500 0.5000
Total 17 34.500
Model Summary
S R-sq R-sq(adj) R-sq(pred)
0.707107 78.26% 75.36% 68.70%
Means
Factor N Mean StDev 95% CI
Marketing Managers 6 8.000 0.894 (7.385, 8.615)
Marketing Research 6 6.500 0.548 (5.885, 7.115)
Advertising 6 5.000 0.632 (4.385, 5.615)
Pooled StDev = 0.707107
Fisher Pairwise Comparisons
Grouping Information Using the Fisher LSD Method and 95% Confidence
Factor N Mean Grouping
Marketing Managers 6 8.000 A
Marketing Research 6 6.500 B
Advertising 6 5.000 C
Means that do not share a letter are significantly different.
Fisher Individual Tests for Differences of Means
Difference SE of Adjusted
Difference of Levels of Means Difference 95% CI T-Value
P-Value
Marketing Re - Marketing Ma -1.500 0.408 (-2.370, -0.630) -3.67
0.002
Advertising - Marketing Ma -3.000 0.408 (-3.870, -2.130) -7.35
0.000
Advertising - Marketing Re -1.500 0.408 (-2.370, -0.630) -3.67
0.002
Simultaneous confidence level = 88.31%
a )from output
Sum of Squares, Treatment | 27.0 |
Sum of Squares, Error | 7.5 |
Mean Squares, Treatment | 13.5 |
Mean Squares, Error | 0.5 |
b ) the value of the test statistic F=27.000
The p-value is0.000 which is less than
.01
since p value is less than 0.01 so we reject Hi and conclude that there are differences among the mean perception scores for the three groups
c)
Difference | Absolute Value | Conclusion |
1 - 2 | 3.67 | Significant difference |
1 - 3 | 7.35 | Significant difference |
2 - 3 | 3.67 | Significant difference |