1. Solve the problem

A 99% confidence interval (in inches) for the mean height of a population is 65.3< <66.9. This result is based on a sample size of 144. Construct the 95% confidence interval.(Hint: you will first need to find the sample mean and sample standard deviation).

2 Use the given degree of confidence and sample data to construct a confidence interval for the population mean . Assume that the population has a normal distribution.

A laboratory tested twelve chicken eggs and found that the mean amount of cholesterol was 225 milligrams with s=15.7 milligrams. Construct a 95% confidence interval for the true mean cholesterol content of all such eggs.

3 Use the given degree of confidence and sample data to find a confidence interval for the population standard deviation . Assume that the population has a normal distribution. Round the confidence interval limits to the same number of decimal places as the sample standard deviation.

The mean replacement time for a random sample of 20 washing machines is 9.4 years and the standard deviation is 2.6 years. Construct a 99% confidence interval for the standard deviation, , of the replacement times of all washing machines of this type.

4 Provide an appropriate response

The confidence interval, 5.06<<23.33, for the population variance is based on the following sample statistics: n= 25, x=42.0 and s=3.1. What is the degree of confidence?