Student Name
Capella University
PSY FPX 7864 Quantitative Design and Analysis
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Date
A one-way ANOVA is utilized when “the researcher needs to compare means on a quantitative Y outcome variable between two or more groups” (Warner, 2012, p. 219). This analysis will illustrate the comparison of quiz3 scores across three sections using ANOVA comparisons.
The analysis involves two variables: section and quiz3. This will include a comparison of the mean quiz3 scores across the three sections. In the context of a one-way ANOVA, the independent variable is referred to as a component (Warner, 2013). The variable “unit” is measured on a nominal scale, while quiz3 is a quantitative variable that employs interval scales. The sample size (N) for the tests is set at 105.
Kolmogorov-Smirnova | Shapiro-Wilk | |||||
---|---|---|---|---|---|---|
Statistic | df | Sig. | Statistic | df | Sig. | |
quiz3 | .148 | 105 | .000 | .946 | 105 | .000 |
a. Lilliefors Significance Correction
The p-value from the Shapiro-Wilk test is .000, indicating a significant deviation from normality. To achieve accurate results, it is recommended that the research includes a larger data set. There are 105 samples in this analysis.
The descriptive output for the three sections, along with quiz3, is as follows: the first section has a mean score of 7.15 with a standard deviation of 1.278, the second section has a mean score of 6.77 with a standard deviation of 1.495, and the third section has a mean score of 7.94 with a standard deviation of 1.560.
quiz3 | N | Mean | Std. Deviation | Std. Error | 95% Confidence Interval for Mean | Lower Bound | Upper Bound | Minimum | Maximum |
---|---|---|---|---|---|---|---|---|---|
1 | 33 | 7.15 | 1.278 | .222 | 6.70 | 7.60 | 4 | 10 | |
2 | 39 | 6.77 | 1.495 | .239 | 6.28 | 7.25 | 4 | 10 | |
3 | 33 | 7.94 | 1.560 | .272 | 7.39 | 8.49 | 6 | 10 | |
Total | 105 | 7.26 | 1.519 | .148 | 6.96 | 7.55 | 4 | 10 |
To compare the mean quiz3 scores, a one-way ANOVA will be employed. The degrees of freedom (df) were 2 between groups and 102 within groups, resulting in a total of 104. The number of independent pieces of knowledge on which a statistic is based (Warner, 2012, p. 56). The F-value in the output is 5.932, which serves as the critical value for rejecting the null hypothesis, leading to its rejection in this analysis.
The performance p-value is .000, which is below the conventional threshold of .05. This p-value further supports the decision to reject the null hypothesis. The effect size is calculated by dividing 25.013 by 240.057, yielding a value of .104, indicating a small to medium effect size.
Source | Sum of Squares | df | Mean Square | F | Sig. |
---|---|---|---|---|---|
Between Groups | 25.013 | 2 | 12.506 | 5.932 | .004 |
Within Groups | 215.044 | 102 | 2.108 | ||
Total | 240.057 | 104 |
Since the ANOVA results indicate that at least one of the sections differs significantly, further examination of the output is necessary. At the 0.05 significance level, the mean difference is noteworthy. The post-hoc (Tukey HSD) results reveal a significant difference in means. The mean difference between Section 3 and Section 2 is 1.170, while the mean difference between Sections 2 and 3 is .788. These findings lend credibility to the assumptions made.
Tukey HSD | (I) section | (J) section | Mean Difference (I-J) | Std. Error | Sig. | 95% Confidence Interval | |
---|---|---|---|---|---|---|---|
Lower Bound | Upper Bound | ||||||
1 | 2 | .382 | .343 | .508 | -.43 | 1.20 | |
3 | -.788 | .357 | .075 | -1.64 | .06 | ||
2 | 1 | -.382 | .343 | .508 | -1.20 | .43 | |
3 | -1.170* | .343 | .003 | -1.99 | -.35 | ||
3 | 1 | .788 | .357 | .075 | -.06 | 1.64 | |
2 | 1.170* | .343 | .003 | .35 | 1.99 |
*The mean difference is significant at the 0.05 level.
The results of the one-way ANOVA indicate that this method is an appropriate tool for providing a valid response to the research question. The test successfully produced output that supported the rejection of the null hypothesis and affirmed the alternative hypothesis, indicating a significant difference in quiz3 mean scores across the three sections. One of the advantages of ANOVA is its ability to evaluate and assess performance across three or more groups. However, a limitation of the test is that if ANOVA indicates a significant difference among groups, a follow-up test is necessary to obtain final results.
George, D. (2016). IBM SPSS Statistics 23 Step by Step (14th ed.) [VitalSource Bookshelf version]. Retrieved from https://bookshelf.vitalsource.com/books/9781134793402
Warner, R. M. (2012). Applied Statistics: From Bivariate Through Multivariate Techniques (2nd ed.) [VitalSource Bookshelf version]. Retrieved from https://bookshelf.vitalsource.com/books/978148330597
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