Research Article

Temporal Aspects of Surface Water Quality Variation Using Robust Statistical Tools

Table 3

Wet season classification function for discriminant analysis (DA) of parameters in mg/L except for temperature, conductivity, and pH.

VariableStandard modeForward stepwise modeBackward stepwise mode
Lambda 𝑃 valueLambda 𝑃 valueLambda 𝑃 value

DO 0.914 0.011 0.914 0.011 0.914 0.011
BOD5 0.851 0.001 0.851 0.001
COD 0.839 0.035 0.839 0.035 0.839 0.035
SS 0.983 0.021 0.983 0.021 0.983 0.021
pH 0.962 0.482
NH3 0.956 0.426
Temperature 0.908 0.160
Conductivity 0.902 0.141
Salinity 0.903 0.144 0.903 0.144
Turbidity 0.878 0.084 0.878 0.084
DS 0.906 0.152
TS 0.894 0.120 0.894 0.120
NO3 0.954 0.406
C l 0.912 0.001 0.912 0.001
P O 4 0.969 0.553

Wilk’s lambda 0.25 0.84 0.48
Chi-square 1.82 1.96 88.45
𝑃 level0.010.030.01