Statistics and sampling.
Statistics and sampling: population, census and sample, observational versus experimental data, random and non-random sampling.
Work through the topic
Learn the method, follow the examples, then try the worksheet.
- 01
Population, census and sample
Identify the intended group and distinguish a census from a sample.
- 02
Observational versus experimental data
Recognise whether a study records existing conditions or deliberately changes a condition.
- 03
Random and non-random sampling
Choose samples by an explicit selection rule rather than convenience.
- 04
Primary/secondary data
Identify a data source and check whether it suits the current question.
- 05
Reviewing numerical displays and summary statistics
Read numerical displays and calculate summaries from raw or frequency data.
- 06
Comparing samples and sample sizes
Compare samples fairly and explain the role of sample size.
- 07
Bias, variation and uncertainty
Separate systematic bias from ordinary variation and communicate limits honestly.
- 08
Planning, conducting and reporting a fair investigation
Carry an investigation from a clear question through collection, analysis and a cautious conclusion.
Topic review
Revisit the key ideas, then choose a practice paper.