Statistical inference — Question 7

QCAA 2021, Paper 1 · 1 mark

Q7 · 2021 · Technology-freeSimple familiar1 mark

QUESTION 7

The mass of a particular variety of cake is claimed to be normally distributed with a mean of

660

grams. A random sample of five of these cakes is found to have a mean mass of

600

grams.

Which option represents an approximate confidence interval for

\mu

based on this sample?

Four confidence-interval diagrams labelled A to D.

ABCD

Question linkOriginal paper

WORKED SOLUTION

Answer B

1 mark

ANSWER

Worked solution

A confidence interval calculated from the sample must be centred at the sample mean,

\bar x=600

g. Among the diagrams, option B is centred at

600

Selects option B.

[1 mark]

Worked explanation by QCE Vault; correct option verified against the QCAA answer key.

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