A social worker is interested in estimating the average length of time spent outside of prison for first offenders who later commit a second crime and are sent to prison again. A random sample of n=100 prison records in the county courthouse indicates that the average length of prison-free life between first and second offenses is 4.2 years, with a standard deviation of 1.1 years. Use this information to construct and interpret a 95% confidence interval for , the average time between first and second offenses for all prisoners on record in the county courthouse.