What Is A Data Set?-referring data science

A data set (or dataset) is a collection of data. In the case of tabular data, a data set corresponds to one or more database tables, where every column of a table represents a particular variable, and each row corresponds to a given record of the data set in question. The data set lists values for each of the variables, such as the height and weight of an object, for each member of the data set. Each value is known as a datum. Data sets can also consist of a collection of documents or files. In the open data discipline, the data set is the unit to measure the information released in a public open data repository. The European Open Data portal aggregates more than half a million data sets. In this field other definitions have been proposed, but currently there is not an official one. Some other issues (real-time data sources,non-relational data sets, etc.)Several characteristics define a data set's structure and properties. These include the number and types of the attributes or variables, and various statistical measures applicable to them, such as standard deviation and kurtosis. The values may be numbers, such as real numbers or integers, for example representing a person's height in centimeters, but may also be nominal data (i.e., not consisting of numerical values), for example representing a person's ethnicity. More generally, values may be of any of the kinds described as a level of measurement. For each variable, the values are normally all of the same kind. However, there may also be missing values, which must be indicated in some way.

In statistics, data sets usually come from actual observations obtained by sampling a statistical population, and each row corresponds to the observations on one element of that population. Data sets may further be generated by algorithms for the purpose of testing certain kinds of software. Some modern statistical analysis software such as SPSS still present their data in the classical data set fashion. If data is missing or suspicious an imputation method may be used to complete a data set

A table is a collection of related data held in a table format within a database. It consists of columns and rows. In relational databases and flat file databases, a table is a set of data elements (values) using a model of vertical columns (identifiable by name) and horizontal rows, the cell being the unit where a row and column intersect. A table has a specified number of columns but can have any number of rows. Each row is identified by one or more values appearing in a particular column subset. A specific choice of columns that uniquely identify rows is called the primary key.

Table" is another term for "relation"; although there is the difference in that a table is usually a multiset (bag) of rows where a relation is a set and does not allow duplicates. Besides the actual data rows, tables generally have associated with them some metadata, such as constraints on the table or on the values within particular columns.

The data in a table does not have to be physically stored in the database. Views also function as relational tables, but their data are calculated at query time. External tables (in Informix or Oracle, for example) can also be thought of as views. In many systems for computational statistics, such as R and Python's pandas, a data frame or data table is a data type supporting the table abstraction. Conceptually, it is a list of records or observations all containing the same fields or columns. The implementation consists of a list of arrays or vectors, each with a name.

Data (treated as singular, plural, or as a mass noun) is any sequence of one or more symbols given meaning by the specific act(s) of interpretation. Data (or datum a single unit of data) requires interpretation to become information. To translate data to information, there must be several known factors considered. The factors involved are determined by the creator of the data and the desired information. The term metadata is used to reference the data about the data. Metadata may be implied, specified, or given. Data relating to physical events or processes will also have a temporal component. In almost all cases this temporal component is implied. This is the case when a device such as a temperature logger receives data from a temperature sensor. When the temperature is received it is assumed that the data has a temporal reference of "now". So the device records the date, time, and temperature together. When the data logger communicates temperatures, it must also report the date and time (metadata) for each temperature.

Digital data is data that is represented using the binary number system of ones (1) and zeros (0), as opposed to analog representation. In modern (post-1960) computer systems, all data is digital. Data within a computer, in most cases, move as parallel data. Data moving to or from a computer, in most cases, moves as serial data. See Parallel communication and Serial communication. Data sourced from an analog device, such as a temperature sensor, must pass through an "analog to digital converter" or "ADC" (see Analog-to-digital converter) to convert the analog data to digital data.

Data representing quantities, characters, or symbols on which operations are performed by a computer are stored and recorded on magnetic, optical, or mechanical recording media, and transmitted in the form of digital electrical signals. A program is a set of data that consists of a series of coded software instructions to control the operation of a computer or other machine. Physical computer memory elements consist of an address and a byte/word of data storage. Digital data are often stored in relational databases, like tables or SQL databases, and can generally be represented as abstract key/value pairs.

Data can be organized in many different types of data structures, including arrays, graphs, and objects. Data structures can store data of many different types, including numbers, strings, and even other data structures. Data pass in and out of computers via peripheral devices.