A research scholar wants to know how many times per hour a certain strand of virus reproduces. The mean is found to be 4 reproductions and the population standard deviation is known to be 2.3. If a sample of 1083 was used for the study, construct the 99% confidence interval for the true mean number of reproductions per hour for the virus. Round your answers to one decimal place.

There are two major tests of readiness for college: the act and the sat. act scores are reported on a scale from 1 to 36. the distribution of act scores in recent years has been roughly normal with mean µ = 20.9 and standard deviation s = 4.8. sat scores are reported on a scale from 400 to 1600. sat scores have been roughly normal with mean µ = 1026 and standard deviation s = 209. reports on a student's act or sat usually give the percentile as well as the actual score. the percentile is just the cumulative proportion stated as a percent: the percent of all scores that were lower than this one. tanya scores 1260 on the sat. what is her percentile (± 1)?