Data, Statistics and Uncertainty
Processing quantitative evidence using tables, graphs, rates, uncertainty, descriptive statistics, probability and suitable inferential tests.
How to study A-level Biology
Move between scales deliberately: identify the biological process, trace matter or information, use quantitative evidence, then evaluate the method and conclusion.
Core concepts
Concept 1
Tables and graphs must preserve units, precision and the distinction between categorical, discrete and continuous variables.
Exam cue: Choose the test from the data type, design and question before calculating.
Concept 2
Spread, uncertainty, anomalies and sample size help judge how strongly data support a conclusion.
Exam cue: Compare the test statistic or probability with the stated critical value or significance level.
Concept 3
Chi-squared, Student's t-test and correlation tests address different questions and require an explicit null hypothesis and significance decision.
Exam cue: Describe the pattern, quantify it from the data and then give a biological explanation.
Risk pitfalls and guardrails
Claiming that correlation proves causation.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Using overlapping error bars as an automatic substitute for the specified statistical test.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Reporting many digits that exceed the precision of the raw measurements.
Guardrail: Do not replace a mechanism with a vague purpose statement, or infer causation from an association without experimental support.
Memory anchors
Null Hypothesis
A null hypothesis states that there is no relevant difference, association or departure from expectation.
Chi-squared Test
Use chi-squared to compare observed categorical frequencies with expected frequencies.
Student's t-test
Use a suitable t-test to assess a difference between two means under its assumptions.
Correlation
A correlation test assesses association, not causation.
Percentage Uncertainty
Percentage uncertainty is absolute uncertainty divided by the measured value, multiplied by 100.
Checkpoint rule
Do the check-up only after you can summarize each concept in one sentence and identify one dangerous pitfall from memory.
Knowledge Check (after reading)
Short check-up to confirm understanding of this module.
Check-up Questions
Which graph is most suitable for showing enzyme rate across a continuous range of temperatures?
Replicate masses are 12.1, 12.4, 12.0, 12.3 and 12.2 g. What is the mean?
Answer all questions to submit.
Next step personalized recommendations
Continue learning
Move forward only after this module is stable.
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