  This short note proposes two additive corrections to a pair of relations
published in Wan et al. in order to extend them to a small sample size
condition. In particular we focus the interest on the possibility to provide an
estimate to the sample standard deviation when knowing only the sample size,
the range and/or the quartiles. Our results allow to explicitely compute
standard deviation, for instance with software R or any spreadsheet, for any
sample size grater than 2. R codes and data are publicly available.
