QCEVault

Sampling and proportions — Question 319

Original QCE Vault practice · 5 marks

Q319 · Practice questionTechnology-activeComplex familiar5 marks

QUESTION 319 (5 marks)

Each of 240240 independently selected voters supports a proposal with probability 0.450.45. Let p^\widehat p be the sample proportion supporting it.
a)
Use a binomial model to determine P(0.4≤p^≤0.5)P(0.4\leq\widehat p\leq0.5), to four decimal places.
[2 marks]
b)
Use a normal approximation without a continuity correction to estimate the same probability, to four decimal places.
[2 marks]
c)
Explain why the two answers need not be identical.
[1 mark]
Question linkSyllabus coverage

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