Which stats test should you use? Flashcards
what stat test do you use for effect of pH on germination?
chi-sqaured
why do you use chi-sqaured for effect of pH on germination?
comparing observed frequencies with expected frequencies
what investigations will use the T-test (unpaired)?
effect of differeing environmental conditions on yield of a crop plant
effect of pollution on vegetation
comparison of leaf length for the same tree species in two different sites
why would you use the t-test unparied?
the variable measure is continuous and is expected to follow bell-shaped curve/ normal distribution and we are interested in comparing mean values
most natural measurements (length, weight) have a normal distribution
what investgation would you use the t-test paired?
comparison of plant growth on two sides of a hedgerow
why wouldyou use the t-test paired?
used when the unpaired t-test applies and there is a natural matching between sites
what investigations will you use the Mann whitney U? (Examples)
comparison of species diversity in mown and unmown turf
lichen distribution related to direction faced (north or south)
comaparison of wildlife in coppicied and uncoppicied woodland
why would you use Mann whitney U?
when want to compare averages but cant assume there is a normal distribution
when calculated or form different sites
can be used instead of t-test but with less significant results
what investigation would you use spearmans rank?
Noise pollution and distance from road
why would you us spearmans rank?
when looking for a rekationship where between two things positive of negative correlation
