A survey will be given to high school students asking how many hours of TV they watch per week. To find the mean number of hours of TV per week, how many students must be sampled to get a 95% confidence interval with a maximum error of 0.3 hours? Use a standard deviation of 1.15 hours.

A study is conducted to find the mean life of a certain manufacturer's car batteries. A random sample of 34 batteries is selected and a mean of 47.5 months with a standard deviation of 7.3 months is found. Find a 95% confidence interval for the mean battery life.

Assume that the heights of women are normally distributed. A random sample of 20 women have a mean height of 62.5 inches and a standard deviation of 1.3 inches. Construct a 98% confidence interval for the population variance, .

A sample of 100 postal employees found that the mean time these employees had worked for the postal service was eight years. Assume we know the standard deviation of the population of times postal service employees have spent with the postal service is five years. Find the 98% confidence interval for the mean time the population of postal service employees have spent with the postal service.

A recent study of 28 randomly selected employees of a company showed that the mean ofdistance they traveled to work was 14.3 miles. The standard deviation of the sample was 2.0miles. Find the 95% confidence interval of the true mean.

Suppose a random sample of 50 baksetball players showed the average height to be 78 inches. Also assume that the population standard deviation is 1.5 inches. Find 99% confidence interval for the population mean height.

Karen wants to advertise how many chocolate chips are in each Big Chip cookie at her bakery. She randomly selects a sample of 63 cookies and finds that the number of chocolate chips per cookie in the sample has a mean of 9 and a standard deviation of 2. What is the 95% confidence interval for the number of chocolate chips per cookie for Big Chip cookies?