9. An airline wants to select a computer software package for its reservation system. Four software packages(1, 2, 3, and 4) are commercially available. The airline will choose the package that bumps as fewpassengers as possible during a month. An experiment is set up in which each package is used to makereservations for 5 randomly selected weeks. (A total of 20 weeks was included in the experiment.) Thenumber of passengers bumped each week is obtained, which gives rise to the following Excel output(TABLE 2): (9 分)

【題組】1). Referring to Table 2, the total degrees of freedom is
(A) 3
(B) 4
(C) 16
(D) 19