animation (version 2.5)

mwar.ani: Demonstration for ``Moving Window Auto-Regression''

Description

This function just fulfills a very naive idea about moving window regression using rectangles to denote the ``windows'' and move them, and the corresponding AR(1) coefficients as long as rough confidence intervals are computed for data points inside the ``windows'' during the process of moving.

Usage

mwar.ani(x, k = 15, conf = 2, mat = matrix(1:2, 2), widths = rep(1, ncol(mat)), 
    heights = rep(1, nrow(mat)), lty.rect = 2, ...)

Arguments

x

univariate time-series (a single numerical vector); default to be sin(seq(0, 2 * pi, length = 50)) + rnorm(50, sd = 0.2)

k

an integer of the window width

conf

a positive number: the confidence intervals are computed as c(ar1 - conf*s.e., ar1 + conf*s.e.)

mat, widths, heights

arguments passed to layout to divide the device into 2 parts

lty.rect

the line type of the rectangles respresenting the moving ``windows''

other arguments passed to points in the bottom plot (the centers of the arrows)

Value

A list containing

phi

the AR(1) coefficients

L

lower bound of the confidence interval

U

upper bound of the confidence interval

Details

The AR(1) coefficients are computed by arima.

References

Robert A. Meyer, Jr. Estimating coefficients that change over time. International Economic Review, 13(3):705-710, 1972.

See Also

arima