IB Biology Internal Assessment Exemplar
How does varying soil acidity affect the growth rate of the plant height of Raphanus sativus in a mesocosm environment?
Loading scores...
Was this exemplar helpful?
Criteria A: Research Design
4/6
0
3
6
Criteria Strands
Research question is situated in a specific agricultural and biological context
Protocol is described in sufficient detail to allow reproduction
Materials and measurement procedures are precise and well documented
Methodological considerations (e.g., sample‐size rationale, pH‐strip accuracy, light variability) are described rather than fully explained
Justification for the choice of five seeds per mesocosm is missing
Details of soil–solution mixing lack clarity to ensure uniform acidity
Criteria B: Data Analysis
3/6
0
3
6
Criteria Strands
Data recording and processing are communicated clearly with well-labelled tables, units, and precision
Graphs include error bars and trend lines, illustrating key trends
Statistical interpretation links F-statistic and p-value correctly to hypothesis testing
Consideration of uncertainties omits instrumental errors (pH meter/caliper precision) and underestimates total uncertainty
ANOVA table contains a degrees-of-freedom error and exclusion of missing data is unexplained
Regression equations and confidence intervals are not reported
Criteria C: Conclusion
4/6
0
3
6
Criteria Strands
Conclusion directly addresses the research question and cites numerical results from R² and ANOVA
Comparison to published pH optima is scientifically justified
The interpretation is consistent with the analysis presented
Effect size (e.g., η²) is omitted, limiting practical interpretation of significance
Conclusion repeats details and could be more concise
Minor lack of emphasis on the primary finding over secondary observations
Criteria D: Evaluation
3/6
0
3
6
Criteria Strands
Specific methodological weaknesses (light variability, invasive measurements, pH-strip accuracy) are identified
Realistic improvements are proposed and linked to these weaknesses
The relative impact of each weakness on validity is not explained or prioritized
Quantitative explanation of how improvements would enhance reliability is absent
No discussion of trade-offs or constraints when implementing proposed improvements