If a trend line has an equation y = 15 + 0.8x, this indicates a positive linear association between the variables x and y. The slope of the line (0.8) is positive, which means that as x increases, y is expected to increase as well. The y-intercept (15) indicates that when x is zero, y is expected to have a value of 15. Overall, the trend line suggests that the data have a positive correlation, meaning that as one variable increases, the other variable also tends to increase