Kendall's tau Correlation Test US Geological Survey, 2005 Data set: Example MKL4a - Mann-Kendall with LOWESS, input type 4 Flow-adjusted concentrations were calculated as residuals from a LOWESS smooth line (f = 0.50) for concentration vs. streamflow The tau correlation coefficient is -0.057 S = -179. z = -0.740 p = 0.4596 The relation may be described by the equation: Residual = 3660.0 + -1.852 * X