Common use of Number of animals Clause in Contracts

Number of animals. T h e objec t ive i s fo r a s ufficie n t nu m be r of p r eg n a n t r a t s t o be exposed t o e n s ur e t h a t a n a deq u a t e nu m be r of offsp r i n g a r e p r o- d u ced fo r n e ur o t oxici t y ev a l u a t io n . A t le a s t 20 li tt e r s a r e r eco mm e n ded a t e a c h dose level. T h i s nu m be r a ss u m es a coefficie n t of v a r i a t io n of 20 t o 25 pe r - ce n t fo r m os t be h a vio r a l t es t s. If, b a sed u po n expe r ie n ce wi t h h i s t o r ic a l co n t r ol d a t a o r d a t a fo r posi t ive co n t r ols i n a give n l a bo r a t o ry , t h e coefficie n t of v a r - i a t io n fo r a give n t a s k i s h ig h e r t h a n 20 t o 25 pe r ce n t , t h e n c a lc u l a t io n of a p- p r op r i a t e s a m ple s izes t o de t ec t a 20 pe r ce n t c h a n ge f r o m co n t r ol v a l u es wi t h 80 pe r ce n t powe r wo u ld n eed t o be do n e. F o r m os t desig n s, c a lc u l a t io n s c a n be m a de a cco r di n g t o Dixo n a n d M a sse y (1957) un de r p a r a g r a p h ( e)(5) of t h i s sec t io n , Ne t e r a n d Wa sse r m a n (1974) un de r p a r a g r a p h ( e)(10) of t h i s sec t io n , S o k a l a n d R o h lf (1969) un de r p a r a g r a p h ( e)(11) of t h i s sec t io n , o r J e n se n (1972) un de r p a r a g r a p h ( e)(8) of t h i s sec t io n .