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However, we only calculate a regression line if one of the variables helps to explain or predict the other variable. This line can be calculated through a process called linear regression. If we think that the points show a linear relationship, we would like to draw a line on the scatter plot. Then proceed to calculate the correlation coefficient r, and check this value for significance. The first step in any regression analysis is to create the scatter plot. However, in regression analysis, all ( x, y) points in the data set will be utilized to develop the linear regression model. When generating the equation of a line in algebra using y = m x + b y = m x + b, two ( x, y) points were required to generate the equation. (c) If b < 0 b < 0, the line slopes downward to the right. (b) If b = 0 b = 0, the line is horizontal. Figure 14.3 Three Possible Graphs of y ^ = a + b x y ^ = a + b x (a) If b > 0 b > 0, the line slopes upward to the right.