Get cellular fraction confidence interval, and also determine if it is greater than zero (eg. if it contains zero). This function return a list with $cell.frac.ci = strings of cell.frac.ci, $is.zero.cell.frac = tell if cell.frac.ci contains zero
get.cell.frac.ci(vi, include.p.value = TRUE, sep = " - ")
clonal evolution tree data frame
include confidence level
separator for the two confidence limits in output string
,p=', 1-vi$p.value,