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.
Penicillium is a fungus, and is the most abundant mold source in soil. There are more than 150 species of penicillium. Penicillium that is more than two-weeks old is bluish in color. Penicillium is a cryophilic fungi, which means it likes the cold, growing best at 34 degrees (the temperature of a refrigerator).enicillium notatum and penicillium chrysogenum are used to make penicillin. In fact, it is sometimes referred to as medicinal mold. Other varieties, such as penicillium roqueforti are used to ripen cheese, although it can also cause mold in grain crops. Penicillium fumiculosum is used in antibotics.