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The heights in inches of orangutans Are normally distributed with a population standard deviation of 3″ and an unknown population mean if a
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The heights in inches of orangutans Are normally distributed with a population standard deviation of 3″ and an unknown population mean if a random sample of 17 orangutans is taken and results in a sample mean of 57″ find the error bound of the confidence interval with a 95% confidence level
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2021-08-02T17:32:39+00:00
2021-08-02T17:32:39+00:00 1 Answers
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Answer: The 95% confidence interval is approximately (55.57, 58.43)
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Explanation:
At 95% confidence, the z critical value is about z = 1.960 which you find using a table or a calculator.
The sample size is n = 17
The sample mean is xbar = 57
The population standard deviation is sigma = 3
The lower bound of the confidence interval is
L = xbar – z*sigma/sqrt(n)
L = 57 – 1.960*3/sqrt(17)
L = 55.5738905247863
L = 55.57
The upper bound is
U = xbar + z*sigma/sqrt(n)
U = 57 + 1.960*3/sqrt(17)
U = 58.4261094752137
U = 58.43
Therefore the confidence interval (L, U) turns into (55.57, 58.43) which is approximate.