← Use statistical methods to make a formal inference

2 What this standard actually asks

One sentence: “Is there a real difference between these two groups in the population, or could this just be sampling variation?”

The shape of the whole report

  • Problem, pose a comparison question about two populations, using a measurement variable.
  • Plan / Data. Describe the sampling: how the samples were taken, sample sizes, and any issues.
  • Analysis. Plot both samples, describe them, then bootstrap to get a confidence interval for the difference between medians.
  • Conclusion. Make the formal inference, justify it from the interval, and discuss limitations.
✓

The single most important wording rule

Your question and your conclusion must both be about the population, not the sample. Write “I want to find out if the median height of all Year 13 boys is greater than…”, never “if the median height of my sample is greater”. Sample-level questions cannot earn the standard.

Practise just this