Converting Variables to Factors with as.factor In R, categorical data is handled using factors. The as.factor() function transforms a vector into a factor type, which is essential for statistical modeling and data analysis. # Sample character vector representing categories gender <- c("Male&...
t-Distribution Principles The Student's t-distribution emerges in statistical inference when evaluating small samples where the population standard deviation is unknown. Conceptually, if a variable $Z$ follows a standard normal distribution $N(0,1)$ and $V$ follows a chi-square distribution with $k$...
R Packages for Phylogenetic Analysis Several specialized R packages facilitate the handling and analysis of phylogenetic data in ecological contexts: pegas: Processes population genetics data, accepting tabular genetic markers and population details to compute gene flow, population structure, and ge...
Overview ggbiplot is a small R package that renders PCA results with ggplot2. It works directly with prcomp() or princomp() outputs and can: Plot samples in the PCA space Color by groups with optional Normal ellipses Display variable loading vectors and an optional correlation circle Produce scree p...