| 释义 |
non-ˈcentral, a.
[non- 3.]
1. Statistics. Having or corresponding to a non-zero mean.
1928Proc. R. Soc. A. CXXI. 670 This interpretation of the distribution..is seen to replace the x2 distribution of the analysis of variance for cases in which the sum of squares corresponding to n1 degrees of freedom is derived theoretically for non-central deviations with fixed central displacements. 1949Biometrika XXXVI. 202 In the case of the well-known tests using x2, t and F, the evaluation of their power functions involves the use of what have been called non-central distributions. 1968P. A. P. Moran Introd. Probability Theory vii. 323 The quantity x2 in (7.121) is then said to have a non-central x2-distribution.
2. Physics. Of a force: not central, i.e. not in general directed along the line joining the bodies it acts between.
1948Physical Rev. LXXIII. 1403/1 (heading) The effect of non-central forces on the collisions of high energy neutrons with protons. 1962Encycl. Dict. Physics V. 610/1 The magnetic forces due to electric currents also have this non-central character. 1966D. L. Livesey Atomic & Nuclear Physics ix. 414 There are noncentral forces between neutron and proton. 1970G. K. Woodgate Elem. Atomic Struct. vii. 107 In the central-field approximation we neglected the residual electrostatic term in the Hamiltonian which represents a non-central force.
Hence non-cenˈtrality, the property of being non-central.
1959H. Scheffé Anal. of Variance 412 The ordinary or central chi-square distribution is the special case of the noncentral distribution when the noncentrality parameter δ = 0. 1969H. O. Lancaster Chi-Squared Distribution xi. 231 It is required to determine the parameters of non-centrality of the test of independence in two dimensions. |