Assignment Problems Section 74 Problems 13 Decide whether th

Assignment Problems
Section 7.4
Problems 1-3. Decide whether the normal sampling distribution can be used. If it can be
used, test the claim about the population proportion p at the given level of significance ? using
the given sample statistics.
1. Claim: p > 0.30; a = 0.05. Sample statistics: p

Solution

1) As n >50 normal sample test can be used.

95% confidence interval for sample proportion 0.35 is (0.2178, 0.4822)

As population mean 0.30 lies in this interval we can take sample proportion = 0.30

Hence claim p >0.30 can be rejected.

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2) n =19 <30. Hence only t test can be used.

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3) N=200 Hence z test is used.

confidence interval at 90% = (0.1263, 0.2137)

As p = 0.22 does not lie in this interval, the claim sample proportion <0.22 is accepted

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4) n >30. Z statistic is used

Confidence interval at 95% = (0.3251, 0.4391)

As 0.35 lies in this interval the conclusion is population proportion = 0.35

p >0.35 is rejected.

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5) Please give these as separate questions with new points.