Question

3 ) The following table represents the outcome of two drug therapies on 63 leukemia patients, The therapies are Prednisone+VCR and Prednisone. The outcomes are Success and Failure Success Failure TOTAL Prednisone+VCR (Trt1) 38 ( _________ ) 4 ( _________ ) 42 Prednisone (2) (Trt 2) 14 ( _________ ) 7 ( _________ ) 21 TOTAL 52 11 63 a) Compute the z-statistic for testing H0: π1 = π2. Also give the one-tailed p-value (for H1 π1 > π2), and the two-tailed p-value (for H1 π1 ≠ π2)

Answer 1

Answers to Questions asked:
(1) Z statistic = 2.3481

(2) one - tailed p-value = 0.0094

(3) two - tailed p- value = 0.0188

(1)

H0: =

H1: >

p1 = 38/42 = 0.9048

p2 = 14/21 = 0.6667

q = 1 - p = 0.1746

Test statistic is:
Z = (p1 - p2)/SE

= (0.9048 - 0.6667)/0.1014 = 2.3481

(2)

Z score = 2.3481

Table of Area Under Standard Normal Curve gives area = 0.4906

One Tail - Right Side Test

p-value = (0.5 - 0.4906) = 0.0094

(3) Two - Tail test

p-value = (0.5 - 0.4906) X 2 = 0.0094 X 2 = 0.0188