in a 2003 study, the Accreditation Council for Graduate Medical Education found that medical residents' mean number of hors worked in a week in 81.7. suppose the number of hours worked per week by medical residents is approximately normally distributed with a standard deviation of 6.9 hours.
1) determine the 75th percentile for the number of hours worked in a week by medical residents.
2) determine the number of hours worked in a week that makes up the middle 80% of medical residents. justify and explain your reasoning

Question

in a 2003 study, the Accreditation Council for Graduate Medical Education found that medical residents' mean number of hors worked in a week in 81.7. suppose the number of hours worked per week by medical residents is approximately normally distributed with a standard deviation of 6.9 hours. 
1) determine the 75th percentile for the number of hours worked in a week by medical residents.
2) determine the number of hours worked in a week that makes up the middle 80% of medical residents. justify and explain your reasoning