Based on the test of homogeneity for variance and correlation in nonlinear regression models with AR(2)errors,the likelihood ratio test and Score test are first discussed.

New dominant forecasting method and redundant measure are defined for combination forecasting method with generalized weight arithmetic average, based on error of power of P .

For the L_p-norm approximation,we determine the weakly asymptotically order for the p-average errors of Lagrange trigonometric interpolation polynomial sequence and Jackson trigonometric interpolation polynomial sequence based on the equidistant interpolation points on the Brownian bridge measure.