How is A2 1 Investigative Project assessed?

It is an internally assessed unit with no terminal written paper. You design and carry out an extended, largely independent investigation and write it up as a portfolio, which your centre marks against CCEA criteria and CCEA moderates. It rewards planning, data collection, statistical analysis, conclusions, critical evaluation and referencing, and it is the A2 counterpart of the AS 1 practical unit.

What is a null hypothesis and why is it used?

A null hypothesis states that there is no significant difference between groups or no significant correlation between variables. It is used because a statistical test is designed to accept or reject it: if the test shows the result is unlikely to have arisen by chance, the null hypothesis is rejected in favour of the alternative hypothesis. Framing the prediction this way lets the conclusion rest on an objective test rather than an impression.

How do you decide whether to accept or reject the null hypothesis?

A statistical test gives a calculated value, which is compared with a critical value at a chosen probability level, usually 0.05 (5 per cent). If the probability that the result arose by chance is less than 5 per cent, the difference or correlation is significant, so the null hypothesis is rejected. If the probability is 5 per cent or more, the null hypothesis is accepted because the result could be due to chance.

Which statistical test should I choose?

Match the test to the data and the question. A test of difference, such as a t-test or a chi-squared test, suits comparisons between groups or between observed and expected frequencies. A correlation test suits a relationship between two measured variables. You should decide on the test during planning so you collect enough repeats and the right kind of data for it to be valid.

What makes a high-mark evaluation in the project?

Judge the reliability of the data from the spread of repeats, judge the validity of the conclusion from how well variables were controlled and how representative the sample was, identify the main random and systematic errors, comment on any anomalies, and propose specific, realistic improvements and sensible extensions. Support the work with references to reliable scientific sources. A critical, balanced evaluation with good referencing separates the strongest projects.

Northern IrelandLife & Health Sciences

CCEA Life and Health Sciences A2 1 Investigative Project: planning, statistical analysis and evaluation of an extended investigation

A guide to the CCEA Life and Health Sciences A2 1 Investigative Project portfolio unit: how it is internally assessed, how to develop a research question and null hypothesis, plan an extended valid investigation, statistically analyse data, draw conclusions, evaluate critically and reference sources.

Generated by Claude Opus 4.814 min readCCEAUpdated 2026-06-16

Reviewed by: AI editorial process; not yet individually human-reviewed

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What this unit demands
Developing the question and planning
Collecting and analysing data
Conclusions, evaluation and referencing
How this unit is examined
Check your knowledge

What this unit demands

A2 1 Investigative Project is the capstone practical unit of CCEA Life and Health Sciences. It is internally assessed, so your centre marks an extended-investigation portfolio against CCEA criteria and CCEA moderates a sample; there is no written paper. It asks more of you than AS 1: you take greater responsibility for the research question, the method, the statistical analysis and a critical, referenced evaluation. The skills it builds reappear in the data questions of the externally assessed A2 units, so it is worth the investment.

This overview pulls the project skills into one workflow. The matching dot-point page works through each stage with practice questions; this guide ties them together.

Developing the question and planning

Strong projects start with background reading from reliable sources, which justifies a focused research question and informs the method. You state a testable hypothesis, usually as a null hypothesis (no significant difference or correlation) so it can be tested statistically. Planning identifies the independent, dependent and control variables, a sensible range and number of values, the apparatus and its resolution, and a full risk assessment. Crucially, you decide the statistical test in advance, so you collect enough repeats and the right data for it to be valid.

Collecting and analysing data

Data should be quantitative, collected with enough repeats for a mean and a statistical test, tabulated with units, and graphed appropriately. A statistical test judges whether a difference or correlation is large enough to be unlikely to have arisen by chance. The calculated value is compared with a critical value at a chosen probability level (commonly 0.05): if the probability of the result arising by chance is below 5 per cent, the null hypothesis is rejected. The analysis describes the pattern and links it to the underlying science.

Conclusions, evaluation and referencing

The conclusion answers the research question using the evidence and the statistical result, related to scientific theory. The evaluation is critical: it judges reliability from the spread of repeats, validity from variable control and sample representativeness, identifies random and systematic errors, considers anomalies, and proposes specific improvements and extensions. References to reliable sources support the work and show academic honesty.

How this unit is examined

Although A2 1 is a portfolio, the same skills appear in the written A2 units as:

Planning and hypotheses. Identifying variables, controls and a null hypothesis.
Data analysis. Choosing and interpreting statistical tests and the 0.05 decision rule.
Graphs and processing. Tabulating, plotting and processing quantitative data.
Evaluation. Classifying errors, judging reliability and validity, and suggesting improvements.

Check your knowledge

A mix of skill questions covering the unit. Attempt them under timed conditions, then check against the solutions.

State what a research question and a null hypothesis are. (2 marks)
Explain why a control is needed in an investigation. (2 marks)
State the purpose of a statistical test. (2 marks)
A test result has a probability of 0.03 of arising by chance at the 0.05 level. State the decision. (1 mark)
Give one situation suiting a test of difference and one suiting a correlation test. (2 marks)
Explain why repeats are needed before a statistical test. (2 marks)
State two features of a high-mark evaluation. (2 marks)
Explain why referencing matters in the project. (2 marks)

Solutions

Q1: A research question is the specific, focused question the investigation answers; a null hypothesis states there is no significant difference or correlation, so a statistical test can accept or reject it.
Q2: A control shows what happens without the independent variable (for example a solvent-only treatment), so any difference can be attributed to the independent variable, supporting validity.
Q3: A statistical test judges whether a difference or correlation is large enough to be unlikely to have arisen by chance, giving an objective basis for the conclusion.
Q4: Reject the null hypothesis: 0.03 is less than 0.05, so the result is significant.
Q5: Test of difference: comparing a measurement between two groups. Correlation test: a relationship between two measured variables.
Q6: Repeats give a mean and a measure of spread, so the test can judge whether a difference exceeds the random variation in the data.
Q7: Any two of: judging reliability from the spread of repeats; judging validity from variable control and sample representativeness; classifying errors; proposing specific improvements and extensions.
Q8: Referencing supports claims with reliable evidence and shows academic honesty, both of which the highest-marked projects demonstrate.

Sources & how we know this

CCEA GCE Life and Health Sciences specification — CCEA (2016)