18 EXERCISE 11 . Interpreting Scatterplots 5.0 5.0 N = 1875 r= 0.86 4.0 y = 0.18 + 0.85x 4.0 - 3.0 3.0 Estimated blood alcohol, g/kg 2.0 2.0 1.0 - 1.0 0.0 - + 0.0 0.0 1.0 2.0 3.0 4.0 5.0 Blood alcohol, g/kg FIGURE 2 SCATTERPLOT AND CORRELATION-REGRESSION ANALY OF THE RELATIONSHIP BETWEEN VENOUS BLOOD-ALCOHOL CONCENTRATIONS (BAC) AND THE CORRESPONDING ESTIMATE OF BAC WITH HAND-HELD BREATH-ALCOHOL INSTRUMENTS. THE DIAGONAL LINES IN THE GRAPH REPRESENT THE LEAST SQUARES REGRESSION LINE AND 95% PREDICTION INTERVAL AND THE DASH LINE IS THE LINE OF IDENTITY. (Kriikku, P., Wilhelm, L., Jenckel, S., Rintatalo, J., Hurme, J., et al. (2014). Comparison of breath-alcohol screening test results with venous blood-alcohol concentration in suspected drunken drivers. Forensic Science International, 239(0379-0738), p. 59.)