posted by Jasmine .
Long term experience showed that after a type of eye surgery, recovery time has a mean of u = 5.3 days in a hospital. A random sample of 40 patients, with this type of eye surgery, were treated as outpatients during recovery and the sample mean recovery time was 4.2 days. Does this indicate that the mean recovery time for outpatients is less than the mean time for those recovering in the hospital? Use a 1% level of significance and assume o = 1.9 days.