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Statistical inference — Question 9

QCAA 2025, Paper 1 · 1 mark

Q9 · 2025 · Technology-freeSimple familiar1 mark

QUESTION 9

An approximate confidence interval for a population mean is calculated based on a sample size of 16 and is found to have width, ww. A second confidence interval is calculated from another sample with the same sample standard deviation. Given that the same zz-value was used for both intervals and the width of the second interval is 2w2w, what is the size of the second sample?
(A)
2
(B)
4
(C)
8
(D)
64
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