Following this procedure, current increase
dependence on trypsin activity was investigated under various
experimental conditions. Their effect and the effect of their interactions
were evaluated applying factorial design of experiments. The
considered factors supposed to affect the response variable were
the 3 level factor (0.5 mM, 1 mM, and 5 mM) analyte concentration
(Factor A), the 2 level factor (6% and 8%) gelatin solution concentration
(Factor B), and the 3 level factor (8 L, 10 L, and 15 L) volume
of the gelatin solution deposited on the electrode surface (Factor
C). The number of treatments and replicates was 18 and 2 respectively,
and the total number of observations was 36. The statistical
significance was determined to be 95% (˛ = 0.05). The hypothesis
of interest (H0: null hypothesis, and HA: alternative hypothesis) for
the factors effects on the response variable are presented below: