www.investopedia.com/terms/l/linearrelationship.asp

A linear relationship (or linear association) is a statistical term used to describe the directly proportional relationship between a variable and a constant.

www.dummies.com/.../math/statistics/how-to-interpret-a-correlation-coefficient-r

In statistics, the correlation coefficient r measures the strength and direction of a linear relationship between two variables on a scatterplot. The value of r is always between +1 and –1. To interpret its value, see which of the following values your correlation r is closest to: Exactly – 1. A perfect downhill (negative) linear relationship.

bolt.mph.ufl.edu/6050-6052/unit-1/case-q-q/linear-relationships

Correlation Coefficient: The correlation coefficient (r) is a numerical measure that measures the strength and direction of a linear relationship between two quantitative variables. Calculation: r is calculated using the following formula: However, the calculation of the correlation (r) is not the focus of this course. We will use a statistics ...

courses.lumenlearning.com/.../chapter/linear-relationships-4-of-4

The correlation ranges between −1 and 1. Values near −1 indicate a strong negative linear relationship, values near 0 indicate a weak linear relationship, and values near 1 indicate a strong positive linear relationship. The correlation is an appropriate numerical measure only for linear relationships and is sensitive to outliers.

explorable.com/linear-relationship

A linear relationship is one where increasing or decreasing one variable n times will cause a corresponding increase or decrease of n times in the other variable too. In simpler words, if you double one variable, the other will double as well. This article is a part of the guide: Select from one of the other courses available: Scientific Method ...

stats.libretexts.org/Bookshelves/Introductory_Statistics/Book:_Introductory...

Two variables \(x\) and \(y\) have a deterministic linear relationship if points plotted from \((x,y)\) pairs lie exactly along a single straight line. In practice it is common for two variables to exhibit a relationship that is close to linear but which contains an element, possibly large, of randomness.

sciencing.com/non-linear-relationship-10003107.html

A nonlinear relationship is a type of relationship between two entities in which change in one entity does not correspond with constant change in the other entity. This can mean the relationship between the two variables is unpredictable, or it might just be more complex than a linear relationship.

support.minitab.com/.../basics/linear-nonlinear-and-monotonic-relationships

A linear relationship is a trend in the data that can be modeled by a straight line. For example, suppose an airline wants to estimate the impact of fuel prices on flight costs. They find that for every dollar increase in the price of a gallon of jet fuel, the cost of their LA-NYC flight increases by about $3500.

en.wikipedia.org/wiki/Linear_regression

In statistics, linear regression is a linear approach to modeling the relationship between a scalar response (or dependent variable) and one or more explanatory variables (or independent variables).The case of one explanatory variable is called simple linear regression.For more than one explanatory variable, the process is called multiple linear regression.

courses.lumenlearning.com/wmopen-concepts-statistics/chapter/linear...

Concepts in Statistics. Module 3: Examining Relationships: Quantitative Data. Search for: Linear Relationships (1 of 4) Use a correlation coefficient to describe the direction and strength of a linear relationship. Recognize its limitations as a measure of the relationship between two quantitative variables.