Correlation - is a statistical measure to quantify the strength of the relationship between two quantitative and continuous variables. The relationship can be one of the following
Positive - increasing one variable would increase the other
Negative - increasing one variable would decrease the other
No Correlation - increasing one variable has no impact on the other
R-Squared is also known as the Coefficient of Determination and is an output from regression analysis. It represents the percentage of response variable variation that is explained by its relationship with one or more predictor variables. In general, the higher the R-squared value, the better the model fits your data. It is always between 0 and 100%.
An application-oriented question on the topic along with responses can be seen below. The best answer was provided by Dipankar Acharya on 4th May 2021.
Applause for all the respondents - Ilavarasi P, Rajender Prasad, Dipankar Acharya