primitives can be found in the help page of \code{\link{yule.time}}.
The model is fitted by minimizing the least squares deviation between
- the observed and predicted distributions of branching times. These
+ the observed and the predicted distributions of branching times. These
computations rely heavily on numerical integrations. If \code{fast =
FALSE}, integrations are done with R's \code{\link[stats]{integrate}}
function. If \code{fast = TRUE}, a faster but less accurate function