1. During December, the mean temperature was 24.9"C, with a standard deviation of 0.88. Construct a 95% confidence interval. 2. A group of researchers wants to estimate the number of years it took for the college students to earn a 6-year bachelor's degrees. Construct a 90% confidence interval estimate of the mean time required for all college students to earn a 6-year bachelor's degrees. From 29 randomly selected students, the mean is 6.5 years with a standard deviation of 0.45 years. 3. The operations manager of a large production plant would like to measure the amount of time (in minutes) a worker takes to assemble a new electronic component. The observed data by the manager are 5.31, 3.32, 3.64, 4.07, 3.98, 4.52, 3.81, 4.70, 8.92. Estimate the mean and standard deviation and construct a 99% confidence interval