Repeated-dose 90-day Oral Toxicity Studies on Whole ... - Europabio

4. Should males and females
be analysed together?
• Physically separating males and females does not
necessarily preclude analysing data from both genders
together but there are good reasons for doing so:
– Analysis across genders for some variables is problematic due
to well-established gender-specific differences in variance,
which experience suggests cannot be readily overcome by the
use of a data transformation.
– Large differences in gender means (e.g., for body and organ
weights) may make results of a combined analysis more
complicated to interpret (Gad, 2006).
– Analysis across genders would be more complex and could be
difficult for some CRO’s to implement correctly.
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