Baseline study Fish, fry and commercial fishery Nysted Offshore ...

Bio/consult as Page 170
The power of the BACI analysis is calculated on the basis of the ratio between the
dispersion of (αβ)ij and the variation between the k replicates within each cell.
The dispersion of (αβ)ij can be expressed as D = ∑(αβ)ij 2 / ((a-1)(b-1) + 1) = 0.1225/2 =
0.0612.
The non-centralising parameter Φ can be expressed as √(nD) / σ.
For each unit of data in the dataset, the above are processed partly to establish the power
for the BACI analysis, with the actual replicant n, and partly to find the n, which would
give a power corresponding to 80%.
SEAS. Baseline study – Fish, fry and commercial fishery Dok. nr. 2148-03-001-rev3 2P.doc