Seasonal Kendall Test for Trend
       US Geological Survey, 2005

 Data set:  Example SKL2b - Seasonal Kendall with LOWESS, input type 2  

 The record is 14 complete water years with  12 seasons per year
    beginning in water year 1972.

 Flow-adjusted concentrations were calculated as
    residuals from a LOWESS smooth line (f =  0.50)
    for concentration vs. streamflow

 The tau correlation coefficient is -0.278
     S =   -189.
     z =  -4.096
     p =  0.0000
     p =  0.0008 adjusted for correlation among seasons
                 (such as serial dependence)
 The adjusted p-value should be used only for data with
    more than 10 annual values per season.

 The estimated trend may be described by the equation:

    Residual =   0.000     +  -0.4935E-01 * Time

    where Time = Year (as a decimal) - 1971.75 (beginning of first water year)