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Confidence interval for the population mean: Use of the t distribution An ecologist randomly samples 14...

Confidence interval for the population mean: Use of the t distribution

An ecologist randomly samples 14 plants of a specific species and measures their heights. He finds that this sample has a mean of 17 cm and a standard deviation of 1 cm. If we assume that the height measurements are normally distributed, find a 95% confidence interval for the mean height of all plants of this species.

What is the lower limit of the confidence interval?

What is the upper limit of the confidence interval?

Carry your intermediate computations to at least three decimal places.

Thanks! :-)

Math   Statistics-And-Probability   
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Homework Answers

Answer #1

Given that, sample size (n) = 14

sample mean = 17 cm

sample standard deviation (s) = 1 cm

t-critical value at significance level of 0.05 with degrees of freedom = 14 - 1 = 13 is,

The 95% confidence interval for population mean is,

Therefore, the lower limit of the confidence interval is 16.4227

and the upper limit of the confidence interval is 17.5773

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