1. A hospital is trying to cut down on emergency room wait times. It is interested in the amount of time patients must wait before being called back to be examined. An investigation committee randomly surveyed 70 patients. The sample mean was 1.5 hours with a sample standard deviation of 0.5 hours. Which distribution should you use for this problem? (Enter your answer in the form z or t_df where df is the degrees of freedom.)

2. the length of time a particular smartphone's battery lasts follows an exponential distribution with a mean of ten months. A sample of 64 of these smartphones is taken. Find the middle 70% for the total amount of time 64 batteries last. (Round your answer to two decimal places.)

3. Suppose that the weight of open boxes of cereal in a home with children is uniformly distributed from three to five pounds with a mean of four pounds and standard deviation of 0.5774. We randomly survey 64 homes with children. Find the probability that the total weight of open boxes is less than 254 pounds. (Round your answer to four decimal places.)

4. The attention span of a two-year-old is exponentially distributed with a mean of about 7 minutes. Suppose we randomly survey 60 two-year-olds. Calculate the probability that an individual attention span is less than 8 minutes. (Round your answer to four decimal places.) 5.Suppose that the length of research papers is uniformly distributed from 8 to 21 pages. We survey a class in which 55 research papers were turned in to a professor. The 55 research papers are considered a random collection of all papers. We are interested in the average length of the research papers.(i)Enter an exact number as an integer, fraction, or decimal._X =

(ii)Round your answer to four decimal places._X =

(iii)Give the distribution of X.(Round your standard deviation to three decimal places.)X~ ________(___,_____)

(iv)Give the distribution of X. (Round your standard deviation to three decimal places.)X ~________(___,_____)

v)Calculate the probability that the professor will need to read a total of more than 860 pages. (Round your answer to four decimal places.)