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Original exam-style questions, mapped to your syllabus. Answers are checked for mathematical equivalence and every attempt updates your mastery.

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12 questions

SA-9709-P6-SE3-0013 marksL1 FoundationCalculatorCI for a mean
A random sample of 2525 from a normal population with standard deviation 44 has mean 5050. Find a 95%95\% confidence interval for the population mean, with limits to 2 decimal places.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE3-0051 markL1 FoundationCalculatorCI for a proportion
A 95%95\% confidence interval for a proportion, from a sample of 400400, is (0.21, 0.29)(0.21,\ 0.29). State the sample proportion.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-Q011 markL1 FoundationCalculatorCI for a mean
The zz-value for a 95%95\% confidence interval is
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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-Q021 markL1 FoundationCalculatorCI for a mean
A 95%95\% confidence interval for μ\mu means that
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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-0044 marksL2 StandardCalculatorCI for a mean
A random sample of 4040 has mean 72.472.4. The population standard deviation is 66. Find a 95%95\% confidence interval for the population mean, with limits to 2 decimal places.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-0054 marksL2 StandardCalculatorCI for a proportion
In a random sample of 200200 people, 4848 are left-handed. Find a 90%90\% confidence interval for the proportion of left-handed people, with limits to 3 decimal places.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE3-0023 marksL2 StandardCalculatorCI for a mean
A random sample of 3636 from a population with standard deviation 1515 has mean 120120. Find a 90%90\% confidence interval for the population mean, with limits to 2 decimal places.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE3-0034 marksL2 StandardCalculatorCI for a proportion
In a random sample of 150150 people, 6060 prefer brand A. Find an approximate 95%95\% confidence interval for the proportion of people who prefer brand A, with limits to 3 decimal places.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE3-0042 marksL2 StandardCalculatorCI for a mean
The population standard deviation is 55 and a sample of 100100 is taken. Find the width of a 99%99\% confidence interval for the mean, correct to 3 significant figures.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-0063 marksL3 ExamCalculatorCI for a mean
The population standard deviation is 66. Find the smallest sample size for which the width of a 95%95\% confidence interval for the mean is less than 22.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE3-0063 marksL3 ExamCalculatorCI for a mean
The population standard deviation is 99. A 95%95\% confidence interval for the mean is (23.2, 26.8)(23.2,\ 26.8). Find the size of the sample used.

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Salam Academy Original Practice · Proposed mark scheme
SA-9709-P6-SE-0086 marksL4 ChallengingCalculatorCI for a mean
A random sample of 100100 values gives Σx=4250\Sigma x=4250 and Σx2=182 700\Sigma x^2=182\,700. Find unbiased estimates of the mean and variance, and a 99%99\% confidence interval for the population mean, with limits to 2 decimal places.

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Salam Academy Original Practice · Proposed mark scheme