Improved one-sided control charts for the mean of a positively skewed population using truncated saddlepoint approximations

This paper develops a truncated saddlepoint (TS) control chart for the mean of a population with a skewed density. This chart requires the estimation of only a few population cumulants from sample data and is relatively straightforward in construction. Performance is assessed at various levels of truncation in terms of type 1 and 2 error rates and compared with other heuristic control charts via the Monte Carlo simulation. The truncated saddlepoint (TS) chart is shown to generally outperform these charts, especially in cases with small sample sizes or high levels of population skewness.