Fields of Anthropology. There are now four major fields of anthropology: biological anthropology, cultural anthropology, linguistic anthropology, and archaeology. Each focuses on a different set of research interests and generally uses different research techniques.
SPC is one of the three categories of Statistical Quality Control (SQC). SQC is a statistical method of analyzing variations in the manufacturing process in order to make it better and more effective. Only a certain number of samples are needed to determine whether the products are acceptable.
Continuous Tone Coded Squelch System (CTCSS) is a generic term used by the mobile radio industry; the technology itself accepts desired signals and rejects undesired ones on a voice radio channel. It's also known under the brand names PL (Private Line) to Motorola users or Channel Guard to GE/Ericsson users.