The paper is based on the Fourier series and use the Chebyshev polynomials wonderfully,gives successfully the distribution and calculation of the sample generalized variance.

Improvement of interval estimation for generalized variance in multivariate normal distribution;

in this paper we give sufficient and necessary conditions that sample avarages and sample variances .

n this paper, we advise two influence measures, those are Cook distance and generalized variance ratio.

Based on the generalized spline subdomain methods, the dynamic displacement modes of the revolutionary shell of the tower is solved.

In order to calculate the cylindrical shells with initial geometrical imperfection, unequidistant B -spline function is used to get the generalized spline subdomain displacement mode whose nodes can be arbitrarily set by interpolating in longitudinal direction and in circumferential direction respectively.