X hits on this document

163 views

0 shares

40 / 41

# Systat: Power analysis

Alpha =        0.05

Model =      Oneway

Number of groups =            4

Within cell S.D. =        1.5

Mean(01) =        7.0

Mean(02) =        8.0

Mean(03) =        9.0

Mean(04) =       10.0

Effect Size =        0.745

Noncentrality parameter =        2.222 * sample size

SAMPLE SIZE   POWER

(per cell)

3          0.373

4          0.551

5          0.695

6          0.802

7          0.876

8          0.925

If we anticipated a gradual decrease of seedling length for increasing amounts of nematodes in the pots and would consider gradual changes of 1 mm on average to be important enough to be reported in a scientific journal…

…then we would reach a power of 80% or more when using six pots or more for each condition.

(Four pots per condition would only bring a power of 55%.)

guessed

 Document views 163 Page views 163 Page last viewed Sun Dec 11 05:04:11 UTC 2016 Pages 41 Paragraphs 368 Words 2988