Assists researchers with planning analysis prior to obtaining
data from Trusted Research Environments (TREs), also known as safe havens.
Marginal distributions of one or more related data frames can be exported
from a TRE and imported elsewhere, where data can be synthesised from them,
with or without user specified correlations, by sampling from a
multivariate cumulative distribution (copula).
The International Stroke Trial (IST) is included as an example dataset
under the ODC-By licence, Sandercock et al. (2011)