Final answer:
The strength of the relationship in a correlational analysis is calculated using the coefficient of determination r², which is the square of the correlation coefficient, r. r² represents the percentage of variation in the dependent variable explained by the independent variable.
Step-by-step explanation:
The strength of the relationship in a correlational analysis can be calculated with B) The coefficient of determination r², which is the square of the correlation coefficient, r. The correlation coefficient measures the strength and direction of the linear relationship between two variables and can range from -1 to +1. A positive value of r indicates that as one variable increases, the other variable tends to increase as well, while a negative value of r indicates an inverse relationship between the two variables. The coefficient of determination, expressed as a percentage, represents the percentage of variation in the dependent variable that is explained by variation in the independent variable.
Although option A (A ratio of explained variability to total variability) might seem correct, it is not the standard measure used in correlational analysis. The correct measure for the strength of the correlation is r², which is specifically called the coefficient of determination and not simply a ratio of explained variability to total variability. Therefore, the correct answer is B) The coefficient of determination r².