The ideal (daytime) noise-level for hospitals is 45 decibels with a standard deviation of 11 db; which is to say, this may not be true. A simple random sample of 80 hospitals at a moment during the day gives a mean noise level of 47 db. Assume that the standard deviation of noise level for all hospitals is really 11 db. All answers to two places after the decimal. (a) A 99% confidence interval for the actual mean noise level in hospitals is ( db, db). (b) We can be 90% confident that the actual mean noise level in hospitals is db with a margin of error of db. (c) Unless our sample (of 80 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between db and db.
The ideal (daytime) noise-level for hospitals is 45 decibels with a standard deviation of 11 db; which is to say, this may not be true. A simple random sample of 80 hospitals at a moment during the day gives a mean noise level of 47 db. Assume that the standard deviation of noise level for all hospitals is really 11 db. All answers to two places after the decimal.
(a) A 99% confidence interval for the actual mean noise level in hospitals is ( db, db).
(b) We can be 90% confident that the actual mean noise level in hospitals is db with a margin of error of db.
(c) Unless our sample (of 80 hospitals) is among the most unusual 2% of samples, the actual mean noise level in hospitals is between db and db.
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