This site uses cookie tracking technologies. Learn more in our Cookie Policy.
Mathematics Analysis and Approaches (AA) IA Exemplar: Orange Weights… | RevisionDojo
Loading document preview...
IB Mathematics Analysis and Approaches (AA) SL Internal Assessment Example
Do the weights of oranges sold at Lidl follow a normal distribution?SL
5
Official IB Result
14/20
Was this exemplar helpful?
Want a report just like this?
Free mini report for your own coursework
Fast feedback on what to improve next
Annotated highlights on your writing
Criteria A: Presentation
3/4
0
2
4
Criteria Strands
A.1Coherence and logical development
Good
A.2Organization and structure
Good
A.3Conciseness and relevance
Moderate
Criteria Feedback
The exploration follows a clear logical sequence with explicit transitions between introduction, data collection, analysis and conclusion.
Section headings, a contents page and consistent sub-headings provide a recognisable and navigable structure.
Tables, graphs and formulae are placed adjacent to the relevant text, facilitating reader comprehension.
Inclusion of lengthy background definitions and the full chi-square table adds unnecessary bulk.
Minor digressions (e.g. extensive copied definitions) interrupt the flow and could be trimmed.
Some sections (bullet-lists of empirical percentages) could be condensed into concise tables for relevance.
1.1·Suggestion
Page 2• Click to view
The table of contents is overly detailed, including minor subsections that clutter navigation. Consider consolidating entries and focusing on main sections to improve conciseness and reader orientation.
1.2·Weakness
Page 3• Click to view
The introduction contains lengthy background copied from sources without synthesis. Trim redundant definitions and focus on your rationale to enhance coherence and maintain reader engagement.
1.3·Suggestion
Page 6• Click to view
Listing empirical percentages in bullet form increases length. Consider summarizing the 68–95–99.7% checks in a concise table to aid readability and relevance.
1.4·Suggestion
Page 7• Click to view
Graph 2’s caption omits parameter values. Add mean and standard deviation on the figure or in caption to reinforce mathematical communication of the normal curve.
1.5·Weakness
Page 9• Click to view
The paragraph ends abruptly and seems incomplete, disrupting flow. Ensure the text is complete and provides a full conclusion or transition to the hypothesis test.
1.6·Suggestion
Page 15• Click to view
The extensive chi-square distribution table in the body disrupts flow. Relocate the full table to an appendix or summary section, citing only relevant critical values in the main text.
1.7·Strength
Page 18• Click to view
The raw data table is appropriately placed in the appendix, keeping the main report concise and focused on analysis.
1.8·Suggestion
Page 20• Click to view
The distribution-vs-weights table lacks clear axis labels or units, making interpretation difficult. Add headings and units for each column to improve presentation.
Criteria B: Mathematical Communication
3/4
0
2
4
Criteria Strands
B.1Mathematical language and notation
Good
B.2Multiple representations
Good
B.3Logical structure and clarity
Good
Criteria Feedback
Appropriate use of mathematical notation (\bar{x}, σ, χ²) with clear explanations accompanying each symbol.
Effective employment of multiple representations: tables, histograms, a superimposed normal curve and shaded pdf.
Logical flow of mathematical argument with step-by-step calculations for the χ² test.
Occasional notation inconsistencies (mixing ≤ and <, using “0_i” instead of “O_i”).
Low-resolution figures with faint axis labels and lack of explicit scale justification.
Verbose formula blocks could be streamlined or moved to an appendix.
2.1·Weakness
Page 4• Click to view
In the frequency table class intervals mix “<” and “≤” inconsistently, and notation for observed frequency appears as “0₁” in formulae. Ensure consistent use of < vs ≤ and correct symbol notation throughout.
2.2·Weakness
Page 4• Click to view
The histogram image is low resolution and axes labels are faint. Improve figure quality and explicitly justify scale choices to enhance clarity and support your analysis.
2.3·Weakness
Page 5• Click to view
The text describing skewness uses informal language and does not link observation to later statistical tests. Tighten mathematical language and connect visual skewness to hypothesis outcomes.
2.4·Weakness
Page 8• Click to view
The description of the GDC function normPdf(x,xˉ,σ) lacks specification of domain and units. Explicitly define input ranges and units to improve clarity.
2.5·Weakness
Page 11• Click to view
The criteria table lists “Not yet met” for expected frequencies before merging. Update the table after combining intervals to reflect accurate met status.
2.6·Suggestion
Page 12• Click to view
The large table of expected frequencies and probabilities could be streamlined by focusing on final merged intervals only. Move detailed interval calculations to appendix.
2.7·Weakness
Page 13• Click to view
In the chi-square calculation block, the notation uses “0_i” instead of “Oi”. Correct this typographical error to maintain clear mathematical communication.
2.8·Suggestion
Page 14• Click to view
The degrees of freedom definition is uncited in text. Include an in-text citation for the formula df=k−1 to strengthen academic rigor in mathematical communication.
2.9·Suggestion
Page 20• Click to view
Figure 1’s legend and units are missing. Include axis labels, units (g for weight), and a legend explaining curve vs data points for full mathematical communication.
Criteria C: Personal Engagement
2/3
0
2
3
Criteria Strands
C.1Independent thinking
Good
C.2Personal approach
Good
C.3Creativity and initiative
Good
Criteria Feedback
Primary data collection and decisions on class merging show clear initiative and independent decision-making.
Personal rationale linking the investigation to curiosity about supermarket produce demonstrates a personal approach.
Suggestions for future extensions reveal thoughtful engagement with methodology.
The approach follows a conventional statistical template with limited novelty or innovative modelling.
Creativity and initiative, while evident, are not sustained at an exceptional level.
Independent thinking is significant but not outstanding, lacking a higher level of originality.
3.1·Strength
Page 17• Click to view
The recommendations for increasing sample size and expanding crates show personal engagement and initiative in refining methodology.
Criteria D: Reflection
2/3
0
2
3
Criteria Strands
D.1Depth of reflection
Good
D.2Critical analysis
Good
D.3Evaluation of outcomes
Good
Criteria Feedback
Meaningful reflection on sampling limitations and reasons for deviation from normality.
Thoughtful analysis comparing the χ² statistic to the critical value with correct interpretation.
Clear evaluation of outcomes with concrete suggestions for improving sampling and methodology.
Reflection is largely confined to the conclusion rather than integrated throughout the report.
Critical analysis remains at a basic level without exploring alternative models or deeper error analysis.
Graphical observations (skewness, bimodality) are not fully woven into the critical reflection.
4.1·Suggestion
Page 3• Click to view
The sampling description is clear but lacks critical reflection at this stage. Introduce brief commentary on potential bias from using a single crate to demonstrate deeper awareness of methodology.
4.2·Suggestion
Page 6• Click to view
The empirical rule bullets are described in prose only. Reflect on reasons for the observed 75% vs theoretical 68% and 91.67% vs 95%, linking deviation to sampling or distributional assumptions.
4.3·Suggestion
Page 7• Click to view
The narrative separates graphical observations from the final test. Integrate comments on skewness and bimodality into your evaluation to deepen critical reflection.
4.4·Strength
Page 16• Click to view
The conclusion succinctly evaluates sampling bias and test outcomes, demonstrating meaningful reflection on limitations and improvements.
Criteria E: Use of Mathematics
4/6
0
3
6
Criteria Strands
E.1Relevance of mathematics
Good
E.2Level appropriateness
Good
E.3Understanding and accuracy
Good
Criteria Feedback
Relevant mathematics (mean, standard deviation, empirical rule, pdf construction, χ² test) effectively addresses the research question.
Mathematics is fully commensurate with SL course level, demonstrating sound application of normal distribution and hypothesis testing.
Computations are largely accurate and correctly interpreted (mean = 237.55 g, σ = 21.07 g, χ² = 10.999, df = 5).
Minor transcription and notation errors (missing formula for σ, unconventional hypothesis statements).
Uneven class-interval merging and axis-limit choices lack full mathematical justification.
Opportunity to deepen analysis (e.g. quantitative misfit measures, impact on degrees of freedom) was not taken.
5.1·Suggestion
Page 5• Click to view
The standard deviation value is quoted as produced by the GDC without showing the formula. Display the calculation or formula σ=n∑(x−xˉ)2 to strengthen mathematical rigor.
5.2·Suggestion
Page 8• Click to view
Adjusting min/max x-values without justification may mislead. Provide reasoning or calculate support points (e.g., mean±3σ) to justify axis limits mathematically.
5.3·Suggestion
Page 9• Click to view
The superimposed histogram and curve are interpreted qualitatively. Quantify misfit (e.g., area difference or KS statistic) to strengthen the connection between visual and statistical assessments.
5.4·Weakness
Page 10• Click to view
The null and alternative hypotheses are conventionally reversed: typically H0 assumes normality. Align hypothesis statements with standard conventions to avoid confusion.
5.5·Suggestion
Page 12• Click to view
Merging class intervals yields uneven widths and reduces df; discuss the impact on test sensitivity and degrees of freedom to show comprehensive use of mathematics.