I'm sorry it was my mistake. The two vectors are found as: dpois(num,0.87) dpois(num,2.08) and represent the discrete density of 8 intervals (num=0:8). -- View this message in context: http://r.789695.n4.nabble.com/Joiny-probability-with-R-tp3314059p3314301.html Sent from the R help mailing list archive at Nabble.com.