A random sample of 89 observation produced a sample mean 25.8 and given population standard deviation 2.6.  (c) find a 99% confidence interval for μ. Round to 2 decimal places.

A random sample of 130130 observations produced a mean of ?⎯⎯⎯=30.2x¯=30.2 from a population with a normal distribution and a standard deviation ?=4.49σ=4.49. (c) Find a 9090% confidence interval for ?μ

Currently patrons at the library speak at an average of 61 decibels. Will this average increase after the installation of a new computer plug in station? After the plug in station was built, the librarian randomly recorded 48 people speaking at the library. Their average decibel level was 66.5 and their standard deviation was 20. What can be concluded at the the α= 0.10 level of significance? a. The test statistic = (please show your answer to 3 decimal places.) b. The p-value = (Please show your answer to 4 decimal places.)

A sample of 50 earthquakes was found to have a sample mean of x ¯ = 1.184 and a sample standard deviation of s = 0.5864. Test the claim that the population of earthquakes has a mean magnitude greater than 1.00. Use a 0.01 significance level. Find the test statistic and critical value used for this test. Round to three decimal places.