This simple function will detect extreme outliers (values above or below 3*interquartile range) in a supplied vector of numbers.

OutCalc(Vals)

Arguments

Vals

A vector of numeric values.

Value

A logical vector where TRUE indicate input values that are extreme outliers.

Details

Outliers can be problematic in the analysis of ratio data when the control treatment (CT) tends to zero and the experimental treatment (ET) does not Then the ET/CT ratio tends towards infinity which can unrealistically skew results’ distributions. This could occur when there are unequal impacts of environmental stressors such as drought, heavy rainfall, pest or diseases between CT and ET.