Stratified sampling is a method of sampling from a population in statistics. When sub-populations vary considerably, it is advantageous to sample each subpopulation (stratum) independently. Stratification is the process of grouping members of the population into relatively homogeneous subgroups before sampling.tratified sampling is a method of sampling from a population in statistics. When sub-populations vary considerably, it is advantageous to sample each subpopulation (stratum) independently. Stratification is the process of grouping members of the population into relatively homogeneous subgroups before sampling.
Hardening (computing) In computing, hardening is usually the process of securing a system by reducing its surface of vulnerability, which is larger when a system performs more functions; in principle a single-function system is more secure than a multipurpose one.
They are porous and cannot hold liquids unless its inside surface has been thoroughly sealed. After the finished piece has air dried and been sealed, it can be decorated for display by using a variety of paints, stains or dyes. There are two basic types of self-hardening clay. The first type, ClaystoneÂ®, works like Plastilina and is usually used over an internal armature for support. The clay material contains both cornstarch hardener and cotton fiber filler to reduce shrinkage and cracking while drying over an armature.