SOLUTION: A magazine includes a report on the energy costs per year for a 32 inch LCD. the article states that 14 randomly selected 32 inch LCDs have a sample standard deviation of $3.74. as

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Question 762925: A magazine includes a report on the energy costs per year for a 32 inch LCD. the article states that 14 randomly selected 32 inch LCDs have a sample standard deviation of $3.74. assume the sample is taken from a normally distributed population. Construct 95% confidence intervals for (a) the population variance (b) the population standard deviation. Interpret the results.
Answer by stanbon(75887) About Me  (Show Source):
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A magazine includes a report on the energy costs per year for a 32 inch LCD. the article states that 14 randomly selected 32 inch LCDs have a sample standard deviation of $3.74. assume the sample is taken from a normally distributed population. Construct 95% confidence intervals for (a) the population variance (b) the population standard deviation. Interpret the results.
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a:::(14-1)*3.74^2/24.736 < var < (14-1)*3.74^2/5.009
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7.3514 < var < 36.30
We have 95% confidence that the variance is between those values.
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b::: sqrt(7.3514) < s < sqrt(36.30)
We have 95% confidence that the standard deviation is between
those values.
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Cheers,
Stan H.