2.5. Statistical analyses
Due to different control values across ages, data were normalized
to percent of the concurrent control for ANOVA (following arc sine
transformation) using dose and age as independent factors; a
significant interaction suggests age differences in the shape of the
dose–response curves whereas a significant age factor with no
interaction suggests similar age differences across the range of
doses. Additional ANOVAs were conducted for each age and tissue
using untransformed ChE data, followed by Dunnett's t-test to
determine dose groups that were different from control. Motor
activity data were analyzed in a similar fashion, but in addition,
vertical and horizontal data were analyzed in adult rats as withinsubject
factors.
In addition to ANOVAs, ChE and motor activity data (expressed as
percent of control) were fit to a logistic equation to determine the 50%