A.1~2 B.3~4 C.8~10 D.15~18
A.0.98和0.96 B.0.97和0.95 C.0.96和0.94 D.0.95和0.93
A.ppf=264kPa B.ppf=282kPa C.ppf=258kPa D.ppf=490kPa