8. A survey found that the American family generates an average of 17.2 pounds of glass garbage each year. Assume the standard deviation of the distribution is 2.5 pounds. Find the probability that the mean of a sample of 55 families will be between 17 and 18 pounds. /0.7135 9. 14. In a survey of 35 adult Americans, it was found that the mean age (in years) that people would like to live to is 87.9 with the standard deviation of 15.5. A. Construct and interpret a 95% confidence interval for the mean. B. How many adult Americans would need to be surveyed to estimate the mean age that people would like to live to within 2 years with 95% confidence