
Dear all, someone could explain why the following example is not a valid
randomization scheme?

 Consider an experiment in which the
six experimental units to be used are permanently ﬁxed in a row and two treat-
ments are to be randomly assigned to the units. (One can think of fruit trees
or a sequence of runs on a piece of laboratory equipment as the experimental
units.) A scientist proposes using an unbiased coin to assign the treatments. He
comes to the ﬁrst unit, tosses the coin, and if it shows a head, assigns treatment
a and otherwise, treatment b. This is repeated at the second unit, and so on, until
three units have been assigned to one of the treatments. Then the remaining units
are assigned to the other treatment. Show that this is not a valid randomization
scheme.

best regards.


_________________________________________________________________
Cansado de espaço para só 50 fotos? Conheça o Spaces, o site de relacionamentos com até 6,000 fotos!
http://www.amigosdomessenger.com.br
	[[alternative HTML version deleted]]

