Dear R People: I just produced the following: x <- seq(-3,3,.01) x[x>= -0.50 & x<= -1.0] numeric(0) x[x>= -0.50 && x<= -1.0] numeric(0) What am I doing wrong, please? This seems strange. Thanks, Erin -- Erin Hodgess Associate Professor Department of Computer and Mathematical Sciences University of Houston - Downtown mailto: erinm.hodgess at gmail.com