The lengths of text messages are normally distributed with a population standard deviation of 3 characters and an unknown population mean. If a random sample of 28 text messages is taken and results in a sample mean of 29 characters, find a 99% confidence interval for the population mean. Round your answers to two decimal places.
z0.10
z0.05
z0.04
z0.025
z0.01
z0.005
1.282
1.645
1.751
1.960
2.326
2.576
You may use a calculator or the common z-values above.
Select the correct answer below:
(28.01,29.99)
(27.89,30.11)
(27.68,30.32)
(28.27,29.73)
(27.54,30.46)
(28.07,29.93)