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 Group
where = 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
l Confidence Interval on t where p= sample proportion ASSUMPTION: n= sample size n°p≥5 z= standard normal score 1(1-p)≥5 for area in tail=a/2 and population infinite /2 O/2 2 2 0 P+2 o 2002 The Wadsworth Group
Confidence Interval on p where p = sample proportion ASSUMPTION: n = sample size n•p 5, z = standard normal score n•(1–p) 5, for area in tail = a/2 and population infinite a 2 −a a 2 n n z: –z 0 z p p p p z p p p p z (1– ) (1– ) : – × + × + © 2002 The Wadsworth Group