Hi! IMHO it would be a good idea to mention in the documentation how quartiles/quantiles are calculated. Phoenix’ results may be different if compared with other statistical software. A simple data set in R: x <- c(63.71,44.09,22.48,57.27,37.40,13.44) quantile(x,0.25,type=6) 20.22 (type=6) is Phoenix’ result (agrees with Mintab and SPSS) 22.48 (type=5) is SAS’ result 26.21 (type=8) is Excel’s results (and also the default in R and S) See also R’s documentation.