Hello,
I am confused with the design of experiment and I need your help. I study
macroinvertebrates from 40 lakes. Each lake was sampled employing stratified
random technique. Each lakes was divided into 3 different lake zones based on
light penetration: near-shore area, transitional, and the deepest part of the
lake. 5 random sediment samples were taken from the near shore area, 5 random
samples in the transitional zone, 25 random samples in the deepest part of the
lake. Sediment type and organisms' counts was recorded for each sample.
To complicate more, 2 different types of equipment were used. Near-shore and
transitional area were sampled with large-area heavy sampler, but the deepest
part of the lake was sampled with small area sampler. I do not know if
different type of equipment should figured in the model since all organisms
counts were calculated as per sq/m.
I want to see if there is the sediment effect on organism counts if lake and
zone are taken into account.I consider the lake to be the random effect . Zone
is the meaningful, it carries information for benthos communities. Zone is
nested within the lake. Sample is nested within the zone and lake. One sample -
one sediment type.
What is the correct way make the model:
My guess is something like: aov(Count ~ Sediment+Error(Lake/Zone/Sample))
Sincerely,
Anna
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