Explain why the data in Table 2 does not enable the researchers to draw proper conclusions about the effectiveness of different types of support. What should the researchers do about this?
AQA
A Level
Statistics
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Psychology Essay: Evaluating the Effectiveness of Support Programs
This essay will analyze the data presented in Table 2 and explain why it is insufficient to draw definitive conclusions regarding the effectiveness of the different types of support programs. We will examine the limitations of the data and propose methodological improvements for future research.
Lack of Baseline Data
A critical flaw in the presented data is the absence of baseline measurements. Without knowing the participants' initial performance or well-being before the support sessions, it is impossible to determine if any observed changes are due to the intervention itself. The data only presents post-intervention scores, preventing a comparison with pre-intervention levels. For example, Group A might have already possessed higher scores than the other groups from the outset. Therefore, attributing their higher post-intervention scores solely to the type of support received would be misleading.
Absence of Measures of Dispersion
Table 2 only provides mean scores for each group, neglecting to include measures of dispersion such as standard deviations (SD). While the means might suggest differences in effectiveness, they fail to capture the variability within each group. A small SD would indicate that scores are clustered closely around the mean, suggesting a more consistent effect of the intervention. Conversely, a large SD suggests a wider spread of scores, implying that some participants benefited significantly more than others within the same group. Without this information, it is impossible to ascertain the consistency and reliability of the observed effects.
Potential Distortion by Outliers
Another limitation arises from the use of the mean as the sole measure of central tendency. Means are susceptible to distortion by outliers – extreme scores that deviate significantly from the rest of the data. A single extremely high or low score within a group can disproportionately influence the mean, potentially creating a misleading impression of the overall group performance. This issue is particularly relevant given the lack of information about the data's distribution and the potential presence of outliers.
Methodological Improvements
To overcome these limitations and enable more robust conclusions, several methodological improvements are recommended:
- Incorporate Baseline Measurements: Prior to implementing the support programs, researchers should record the participants' relevant scores on the same measures used post-intervention. This will allow for a direct comparison between pre- and post-intervention scores, providing a clearer indication of the intervention's impact.
- Include Measures of Dispersion: Reporting standard deviations alongside the means will provide crucial information about the variability within each group. This allows for a more nuanced understanding of the intervention's effects and helps identify potential subgroups who respond differently to the support provided.
- Consider Alternative Measures of Central Tendency: Instead of solely relying on the mean, researchers could utilize the median, which is less susceptible to outlier influence. This would provide a more stable representation of the typical score within each group, especially when dealing with potentially skewed data.
Conclusion
In its current form, Table 2 lacks the necessary information to draw reliable conclusions about the effectiveness of the different support programs. The absence of baseline data, measures of dispersion, and the potential for outlier distortion severely limit the interpretability of the findings. By incorporating the suggested methodological improvements – including baseline measurements, standard deviations, and considering alternative measures of central tendency – future research can provide a more accurate and meaningful assessment of the effectiveness of such interventions.