1'. City planners wish to estimate the mean lifetime of the most commonly planted trees in urban settings. A sample of 19 recently felled trees yielded mean age 32.? years with standard deviation 3.1 years. Assuming the lifetimes of all such trees are normally distributed, construct a 99.9% confidence interval for the mean lifetime of all such trees. '3. To estimate the number of calories in a cup of diced chicken breast meat, the number of calories in a sample of four separate cups of meat is measured. The sample mean is 211-9 calories with sample standard deviation 9.9 calorie. Assuming the caloric content of all such chicken meat is normally distributed, construct a 95% condence interval for the mean number of calories in one cup of meat. 9. A college athletic program wishes to estimate the average increase in the total weight an athlete can lift in three different lifts after following a particular training program for sin weeks. Twenty-five randomly selected athletes when placed on the program exhibited a mean gain of 4?-3 lb with standard deviation [3.4 lb. Construct a 99% confidence interval for the mean increase in lifting capacity all athletes would experience if placed on the training program- Assume increases among all athletes are normally distributed. 19.To test a new tread design with respect to stopping distance, a the manufacturer manufactures a set of prototype tires and measures the stopping distance from T9 mph on a standard test car. A sample of 25 stopping distances yielded a sample mean 133 feet with sample standard deviation 9 feet. Construct a 99% confidence interval for the mean stopping distance for these tires. Assume a normal distribution of stopping distances. 11.A manufacturer of chokes for shotguns tests a choice by shooting 15 patterns at targets 41] yards away with a specified load of shot. The mean number of shot in a 39-inch circle is 53.9 with standard deviation 1.5. Construct an 9936 confidence interval for the mean number of shot in a 39-inch circle at all} yards for this choke with the specified load. Assume a normal distribution of the number of shot in a 39inch circle at 49 yards for this choke. llln order to estimate the spealcing vocabulary of three-yearold children in a particular socioeconomic class, a sociologist studies the speech of four