At minimum, there must be values and counts of those values, or an absolute frequency. There can many different pieces of information in a frequency table. You should use frequency tables, or shortly frequencies. Continuous variables can be open or closed intervals or true numerical variables, or true numeris.ДЇor more information, see the article: Introduction to data science, data understanding and preparation Q5: How do you get an overview of a distribution of a discrete variable?

Continuous variables have an infinite pool of values.

Discrete variables can be categorical, ordinal, or dichotomous.

Discrete variables have a limited pool of possible distinct values.

No, there are two basic classes of variables: In an R or Python data frame, you can use numerical positional indexes to read the data values in their position.ДЇor more information, see the article: Introduction to data science, data understanding and preparation Q4: Do all variables measure data values in the same way? In order to read a value from a table, you need to know the table name, the key of the row, and the name of the column. Because the order of rows and columns in a set is not defined, you cannot refer to the data values by their position. An SQL Server table represents a set, a data frame a matrix. However, unlike with R, where the data frame structure is a part of the core engine, you need to use an additional library called pandas in Python in order to get data frames available.ДЇor more information, see the article: Introduction to data science, data understanding and preparation Q3: Is there a difference between a table and a data frame? Python follows R and also introduces data frames. R introduces the structure called data frame. Set theory is the basis for the relational model. SQL Server tables follow the relational model, meaning that they represent a set.

A table can by physical or a virtual one, which is a view. In SQL Server, you store the dataset you are analyzing in a table. Is this a person, a family, an order? Then you collect all of the knowledge about each case you can get and store this information in the variables.ДЇor more information, see the article: Introduction to data science, data understanding and preparation Q2: What are the data structures you use to store the datasets? The first important question you need to answer when you start a data science project is what exactly is your case. Cases are described by their variables, which represent the attributes of the entities.

Datasets consists of cases, which are the entities you analyze. Q1: In the data science terminology, how do you call the data that you analyze?

Basic data science questions