Theory R functions Examples Exercise

Simple EDA (Exploratory Data Analysis):

• boxplot - draws the boxplot of data; with argument outline = TRUE (default setting) draws also the outliers;
• hist - histogram with distribution of values in the variable;
• qqnorm, qqline - draws QQ plot (comparing the quantiles of values in variable x to quantiles of normal distribution) and adds the line for comparison.
• pairs - draws the pairwise relationships between variables in the matrix/data.frame; the original pairs function can be extended for panel functions from Numerical Ecology with R, which gives quite interesting tool for data overview (see details here).

Data transformation

• sqrt
• log, log10, log1p

Data standardization

• scale
• decostand (library vegan)