The following is a set of student data on the vapor pressure of liquid ammonia, obtained in a physical chemistry laboratory course.
(a) Find the indicated enthalpy change of vaporization. 

Temperature (^◦C)            Pressure (Torr)
−76.0....................................................51.15
−74.0....................................................59.40
−72.0....................................................60.00
−70.0....................................................75.10
−68.0....................................................91.70
−64.0..................................................112.75
−62.0..................................................134.80
−60.0...................................................154.30
−58.0...................................................176.45
−56.0...................................................192.90

(b) Ignoring the systematic errors, find the 95% confidence interval for the enthalpy change of vaporization.