| In the Design
of Experiments it is usual
to carry out several tests at each treatment,
this allows the amount of variation (experimental
error) to be estimated. If each treatment
is tested four times then there are four
replications of the design, as long as the
important requirement that the order of
the runs is randomized
is satisfied.
The purpose of randomization is to remove
systematic error. If the runs are not randomized
but each treatment is repeated several times
before moving on to the next, then that
is referred to as a 'repeat' or 'repetition'
rather than a 'replication'.
If the runs are not randomized the ANOVA
analysis should not be carried out using
the repeats as individual readings. Instead
the mean of the repeats should be treated
as a single reading
|
