Pseudoreplication is defined as
the use of inferential statistics to test for treatment effects with data from experiments
where either treatments are not replicated (though samples may be) or replicates are not statistically independent.
What is pseudoreplication statistics?
Pseudoreplication occurs
when observations are not statistically independent
, but treated as if they are. This can occur when there are multiple observations on the same subjects, when samples are nested or hierarchically organised, or when measurements are correlated in time or space.
What is pseudoreplication example?
Here are some other examples of pseudoreplication:
treating multiple leaves from the same plant as replicates
; treating multiple plants from the same pot or flat as replicates; treating multiple samples from the same plot as replicates.
What causes pseudoreplication?
Implicit pseudoreplication occurs
when standard errors (or confidence limits) are estimated within experimental units
. As with other sources of pseudoreplication, treatment effects cannot be statistically separated from effects due to variation among experimental units.
What are Pseudoreplicates?
Heffner et al
3
distinguish a pseudoreplicate from a true replicate, which they characterize as “
the smallest experimental unit to which a treatment is independently applied
.” Most models for statistical inference require true replication. True replication permits the estimation of variability within a treatment.
How can Pseudoreplication be prevented?
To avoid pseudoreplication all you need to do is
clearly communicate your sample size
. For instance: From 5 independent sites, we collected 10 samples per week, over a total of 4 weeks ( n = 10 per week, 40 per site, 200 total). Hope this helps!
What are the experimental units in an experiment?
experimental unit, in an experimental study, a physical entity that is the primary unit of interest in a specific research objective. Generally, the experimental unit is
the person, animal, or object that is the subject of the experiment
.
How do you deal with Pseudoreplication?
The two main ways of dealing with pseudoreplication are: (1)
average the pseudoreplicates to obtain one value per genuine replicate
, or (2) use a more sophisticated approach that captures the structure of the data where the pseudoreplicates are nested under the genuine replicates, such as a multilevel/hierarchical ...
What is spatial Pseudoreplication?
Pseudoreplication occurs when you analyse the data as if you had more degrees of freedom than you really have. ... spatial pseudoreplication,
involving several measurements taken from the same vicinity
.
What is temporal Pseudoreplication?
g) Temporal pseudoreplication occurs
when multiple samples are taken from each experimental unit sequentially over time
, and the sampling dates are taken to represent replicated treatments.
What is demonic intrusion?
demonic intrusion is
when you don’t know it is happening
, non demonic intrusion is when you cant plan for unexpected changes in experiment therefore more replication is needed.
What is an independent replicate?
Replicating the experiment by independent researchers. Repeating the whole experiment by researchers that were not part of the initial experiment. This occurs
when a paper is published and others try to obtain the same results
.
What happens if the independence assumption is violated?
What happens if you violate the Assumption of Independence? In simple terms, if you violate the assumption of independence,
you run the risk that all of your results will be wrong.
What is simple Pseudoreplication?
Simple pseudoreplication is
where there is only a single replicate per treatment, but subsamples are taken from each area
. Temporal pseudoreplication is also where there is only a single replicate per treatment, but multiple samples are taken over time. ... In observational studies simple pseudoreplication is common.
What replicate means?
:
to repeat or duplicate
(as an experiment) intransitive verb. : to undergo replication : produce a replica of itself virus particles replicating in cells. replicate. noun.
What do you mean by DNA replication?
DNA replication is
the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules
. ... Once the DNA in a cell is replicated, the cell can divide into two cells, each of which has an identical copy of the original DNA.
