Question

why is there still a need for graphical evaluation of data in R² or the coefficient of determination of the best fit line?​

Answer 1

Answer:

The coefficient of determination is a complex idea centered on the statistical analysis of models for data. The coefficient of determination is used to explain how much variability of one factor can be caused by its relationship to another factor.

Explanation:

R-squared is a goodness-of-fit measure for linear regression models. This statistic indicates the percentage of the variance in the dependent variable that the independent variables explain collectively. ... After fitting a linear regression model, you need to determine how well the model fits the data.