1. Definition
1.1. Statistical indicators that make it possible to summarize the data in a single one, or to divide its distribution into intervals of the same size
2. Importance
2.1. They help us to group data and even to decode them
2.2. These are the main and basic knowledge in statistics
3. Classification
3.1. Non-central position measurements
3.1.1. Quartile
3.1.1.1. The lower values of the distribution are below the first one
3.1.1.1.1. Q1
3.1.1.2. The middle or median are the lower values equal to the second quartile
3.1.1.2.1. Q2
3.1.1.3. The upper values are represented by the third quartile
3.1.1.3.1. Q3
3.1.2. Quintile
3.1.2.1. The distribution is divided into five parts
3.1.2.2. There is no value that divides the distribution into two equal parts
3.1.3. Decile
3.1.3.1. The data is divided into ten equal parts
3.1.3.2. The are nine deciles
3.1.3.2.1. D1 to D9
3.1.4. Percentile
3.1.4.1. The distribution is divided into one hundred parts
3.1.4.2. It has, in turn, an equivalence with deciles and quartiles
3.2. Central position measurements
3.2.1. Arithmetic, geometric or harmonic measurement
3.2.1.1. These are three central measures that indicate a weighted average of the data
3.2.1.1.1. The arithmetic mean
3.2.1.1.2. Geometry
3.2.1.1.3. The harmonic measurement
3.2.2. Median
3.2.2.1. Divide the distribution into two equal parts
3.2.2.2. It is very useful in variables such as income or salaries, while it is closely related to the median and some of the quantiles seen
3.2.3. Statistical mode
3.2.3.1. It informs us about those that are repeated on more occasions
3.2.3.2. This measure is very useful in market research when we measure an impression about a product with a likert scale