This paper presents a new way to construct confidence intervals for the
unknown parameter in a first-order autoregressive, or AR(1), time series.
Typically, one might construct such an interval by centering it around the
ordinary least-squares estimator, but this new method instead centers the
interval around a linear combination of a weighted least-squares estimator and
the sample autocorrelation function at lag one. When the sample size is
small and the parameter has magnitude closer to zero than one, this new
approach tends to result in a slightly thinner interval with at least as much
coverage.
Keywords
confidence interval, autoregressive parameter, weighted
least squares, linear combination