HP 113394 User Guide - Page 98

98 Section 6: Statistics Functions Example: Check the reliability of the linear estimate in the preceding example by displaying the correlation coefficient. Keystrokes Display ~ 0.90 The correlation coefficient is close to 1, so the sales calculated in the preceding example is a good estimate. To graph the regression line, calculate the coefficients of the linear equation y = A + Bx. 1. Press 0gR to compute the y-intercept (A). 2. To compute the slope of the line (B) in RPN mode, press 1gR~d~-. To compute the slope of the line (B) in ALG mode, press these keys: 1gR~d-~}. Example: Compute the slope and intercept of the regression line in the preceding example. Keystrokes (RPN mode) Display 0gR 1 gR~d~- 15.55 0.001 y-intercept (A); projected value for x = 0. Slope of the line (B); indicates the change in the projected values caused by an incremental change in the x value. Keystrokes (ALG mode) Display 0gR 15.55 1gR~d-~} 0.001 y-intercept (A); projected value for x = 0. Slope of the line (B); indicates the change in the projected values caused by an incremental change in the x value. The equation that describes the regression line is: y = 15.55 + 0.001x File name: hp 12c pt_user's guide_English_HDPMF123E27 Page: 98 of 275 Printed Date: 2005/8/1 Dimension: 14.8 cm x 21 cm