Its only advantage over the random sampling technique is simplicity. Systematic sampling is frequently used to select a specified number of records from a computer file. Stratified sampling is commonly used probability method that is superior to random sampling because it reduces sampling error. A stratum is a subset of the population that share at least one common characteristic. Examples of stratums might be males and females, or managers and non-managers.
| references | in Wikidata. Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. Its name comes from Greek mythology, specifically Niobe, who was the daughter of Tantalus, the namesake of tantalum.
Bifidobacterium Longum INTRODUCTION Bifidobacterium longum, also commonly referred to a B. longum, is a non-pathogenic probiotic that is found naturally in the gastrointestinal tract (GIT) and the vagina.As a probiotic, B. longum may provide health benefits to individuals as B. longum works to prevent disease.. longum, as well as other types of âgoodâ bacteria, have what is considered a symbiotic relationship with human beings. This means that the relationship between B. longum and human begins is mutually beneficial. B. longum ferments sugars into lactic acid thereby lowering pH levels in the intestine (2).