l Confidence Interval: u, o Unknown where x= sample mean ASSUMPTION: s= sample standard Population deviation approximately n sample size normal and t=t-score for area infinite in tail=a/2 /2 O/2 t t x-t x+t o 2002 The Wadsworth Groupwhere = sample mean ASSUMPTION: s = sample standard Population deviation approximately n = sample size normal and t = t-score for area infinite in tail = a/2 df = n – 1 a 2 −a a 2 n s x x t n s x x t t t t × + × + : – : – 0 x Confidence Interval: µ, s Unknown © 2002 The Wadsworth Group