Constructing Confidence Intervals In Exercises 35 and 36, you are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals...

Constructing Confidence Intervals In Exercises 35 and 36, you are given the sample mean and the population standard deviation. Use this information to construct the 90% and 95% confidence intervals for the population mean. Interpret the results and compare the widths of the confidence intervals. If convenient, use technology to construct the confidence intervals.

35. Gasoline Prices From a random sample of 48 days in a recent year, U.S. gasoline prices had a mean of $3.63. Assume the population standard deviation is $0.21. (Source: U.S. Energy Information Administration)

36. Sodium Chloride Concentration In 36 randomly selected seawater samples, the mean sodium chloride concentration was 23 cubic centimeters per cubic meter. Assume the population standard deviation is 6.7 cubic centimeters per cubic meter.