When all the points fall on the regression line, the value of the correlation coefficient is

When all the points fall perfectly on the regression line, the correlation coefficient is exactly +1 or -1, depending on the direction of the relationship. A value of +1 indicates a perfect positive correlation, meaning as one variable increases, the other does too in a linear fashion. Conversely, a value of -1 signifies a perfect negative correlation, where one variable decreases as the other increases. In essence, this scenario represents full predictability between the two variables! In practice, achieving such a perfect correlation is rare in real-world data; most datasets will show some degree of variability and noise. However, striving for high correlation can provide meaningful insights in fields like finance, social sciences, and natural sciences, guiding decision-making and strategies based on the relationships observed in the data!