Study on waking sleepers early. Scientists have discovered increased levels of the hormone...

Study on waking sleepers early. Scientists have discovered increased levels of the hormone adrenocorticotropin in people just before they awake from sleeping (Nature , January 7, 1999). In the study described, 15 subjects were monitored during their sleep after being told that they would be woken at a particular time. One hour prior to the designated wake-up time, the adrenocorticotropin level (pg/mL) was measured in each, with the following results:

a. Use a 95% confidence interval to estimate the true mean adrenocorticotropin level of sleepers one hour prior to waking.

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b. Interpret the interval you found in part a in the words of the problem.

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c. The researchers also found that if the subjects were woken three hours earlier than they anticipated, the average adrenocorticotropin level was 25.5 pg/mL. Assume that μ = 25.5 for all sleepers who are woken three hours earlier than expected. Use the interval from part a to make an inference about the mean adrenocorticotropin level of sleepers under two conditions: one hour before the anticipated wake-up time and three hours before the anticipated wake-up time.