With iodide, the solvate $\ce{NaI \cdot 3(CH3)2CO}$ can be formed, in which each $\ce{Na+}$ is coordinated by 6 acetone ligands via oxygen lone pairs, and the $\ce{I-}$ ions fill in the gaps between these octahedral units, being surrounded by the methyl groups of the acetones.
Randomization is a sampling method used in scientific experiments. It is commonly used in randomized controlled trials in experimental research.
A Randomized Controlled Trial is an experiment or study conducted in such a way that as many sources of bias as possible are removed from the process. Basically, scientific errors of the past have taught us where we can go wrong, drawing false conclusions from our research.