Now Playing: Group-Sequential Tests for Two Means (5:59)

"PASS 13 is fantastic! Better than my new dishwasher and microwave combined."

Dr. Barbara Tabachnick, CSUN, Author

"I really love this version of NCSS and as teacher and researcher in a medical field I can say there aren't many things I miss in it... The help system is another strong feature; the transformations interface is one of my favorites as well."

Dr. Adrian Buzea