mapply, vapply, lapply, sapply, tapply, map,rapply

This document proposes a new method for determining the missing data in a numeric time series. It is similar to the concept of earth porosity and is better than just measure the percentage of missing data.

Various methods for implementing stationary test for time series data.

This is an improved version of Granger causality test for time sereis using Tota Yamada's method and example.