Justifying an inference

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What this lesson covers

  • State the population and parameter.
  • Give the interval and units.
  • Discuss the design and the assumptions.
Worked example

Sentence by sentence

  • A random sample of 100 adults.
PartSentence
ClaimI am fairly sure the mean height of adults in this town is between 168.04 and 171.96 cm.
MethodA 95% interval from a random sample of 100.
LimitsPeople who declined to take part could differ from those who did.

Common mistakes

  • Writing we are 95% sure with no population named.
    Name the population and the units.
  • Ignoring non-response.
    Say how it could affect the result.

Your turn

  • 1. Name two things to check about the sample.
Show answer

1. Whether it was random, and whether non-response could bias it

Summary

What to take away

  • Claim, method, limits.
  • Evidence for every statement.

More in AS 91582

Sampling variability and bootstrappingNotesFormal confidence intervalsNotesComparing populationsNotesJustifying an inferenceNotes

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