Can height predict lung capacity?

AI SLAI HLAA SL Accessible Also in: Statistics, Sport

Research question

How strongly is vital capacity (measured with a spirometer) related to height among students in my school, and do students who play wind instruments or endurance sports have larger residuals?

Adapt it: change the place, the data or the comparison until the question is yours.

Why it makes a good exploration

Doctors use predicted lung capacity based on height, age and sex. Measuring classmates (with consent and a school spirometer) and testing whether musicians and athletes beat the prediction gives your own dataset and a clear second question.

The mathematics you'll need

Scatter plots, correlation and linear regression
Residuals and group comparisons
t-test on residuals (AI)
Sampling and bias

Course labels show where a technique sits; using maths from outside your course is fine if you explain it clearly and say it is new to you.

Where the data comes from

Use a school spirometer (biology department) with consent; record height, sex and activities; 40+ students.

Desmos graphing calculator — Free graphing and regression (y₁ ~ ax₁ + b) — fit models to your data and show residuals.

Cite every source in a footnote where you use it and in your bibliography. Check the licence of any dataset you download.

A possible outline

Plan ethically with your teacher.
Collect measurements with a consistent method.
Fit regression models by sex.
Compare residuals of musicians/athletes.
Reflect on technique and effort effects.

Pitfalls that cost marks

Inconsistent technique (take the best of three).
Mixing sexes in one regression without comment.
Too few musicians/athletes to compare.

Showing personal engagement

Include yourself and explain your own residual.
Compare with published reference equations.
Discuss what “normal” lung capacity means.

See Criterion C: personal engagement for what examiners look for.

Taking it further

Fit a model with height and sex together and compare with a published clinical equation.

Turn this idea into your IA

Plan this IAOpens the planner with this question, the maths and data sources filled in. Desmos workspacePlot your data, fit models and keep your graphs with your plan. AI feedback on a draftCriterion-by-criterion feedback with evidence from your own text. Coaching, not rewriting. Examiner reviewPete, a practising IA examiner, reads your draft and talks it through with you (€100).