1 Demodex mites. 2  Scabies mites which live predominantly on animals, can also infect humans. 3  They don't normally complete their life cycle in humans, but can make for intensely itchy nights, for up to ten days. 4  Bird mites causing the sensation of crawling on the skin, especially at night.
The data set lists values for each of the variables, such as height and weight of an object, for each member of the data set. Each value is known as a datum. The data set may comprise data for one or more members, corresponding to the number of rows. The term data set may also be used more loosely, to refer to the data in a collection of closely related tables, corresponding to a particular experiment or event. An example of this type is the data sets collected by space agencies performing experiments with instruments aboard space probes.
A set is a collection of distinct, symbols in ordered objects. Sets are typically collections of numbers, though a set may contain any type of data (including other sets).The objects in a set are called the members of the set or the elements of the set.A set should satisfy the following: 1) The members of the set should be distinct. If A and B are two sets, then difference of A and B is the set A-B consisting of all the elements which are elements of A but are not elements of B. 2  Complement of a set A, written as A' or A C is the set consisting of all the elements of which do not belong to A. 3  Thus A' = {x | x and xA}.