Question

In clinical tests of adverse reactions to the drug

Viagra, 51 of the 734 subjects in the treat

ment group experienced dyspepsia (indigestion) and

22 of the 725

subjects in the placebo group experienced dyspepsia (based on data from Pfizer Pharmaceuticals). Using a

0.05 significance level, test the claim that the proportion of dyspepsia cases among V

iagra users (group 1)

is greater than the proportion of dyspepsia cases among non

-Viagra users (group 2).

a)

What proportion of Viagra users experienced dyspepsia?

A. 0.030

B. 0.069

C. 0.073

D. 0.050

b) Based on the description above, w

hat

are the

null

and alternative hypothes

es, respectively

?

A.

p

1

=

p

2

,

p

1

≠

p

2

B.

p

1

>

p

2

, p1 < p2

C.

p

1

≤

p

2

,

p

1

>

p

2

D.

p

1

<

p

2

,

p

1

≥

p

2

c)

What is the value of the calculated z test statistic use

d to test the given hypothesis?

A. 0.048

B. 0.59

C. 3.43

D. 11.75

5

d)

What is the

p

-

value (corresponding to your test statistic)?

A. 0.0003

B. 0.05

C. 0.95

D. 0.9997

E. Cannot be determined from the given information

e)

What conclusion should you make based on the given data?

A. Reject H

0

and conclude there is not sufficient evidence to support the claim that dyspepsia occurs at a higher

rate among Viagra users than those who do not use Viagra.

B. Reject H

0

and conclude there is sufficient evidence to support the

claim that dyspepsia occurs at a

higher rate among Viagra users than those who do not use Viagra.

C. Accept H

0

and conclude there is sufficient evidence to support the claim that dyspepsia occurs at a

higher rate among Viagra users than those who do not

use Viagra.

D. Fail to reject H

0

and conclude there is not sufficient evidence to support the claim that dyspepsia

occurs at a higher rate among Viagra users than those who do not use Viagra.

Answer 1

Data Summary
	n	Proportion
p1	734	51/734 = 0.06948229
p2	725	25/725 = 0.03034483

a) Proportion of Viagara users experiencing dyspepsia

     p1 = 51/734 = 0.069

     Answer :

     B.    0.069

b) Since we want to test if Group 1 proportion is greater than Group 2 proportion

Answer :The null and alternative hypotheses are   

C.

Ho : P1 ≤ P2                                        P1 and P2 are the population proportions for
Ha : P1 > P2                                         dyspepsia cases among Viagra users (group 1) and non-viagara group (group 2)

c)   z-statistic is calculated using following formulae

Pooled Proportion p̂  
p̂ = 0 .050034  
  
Standard Error SE  
SE = 0 .011416  
  
Test Statistic Z-statistic  
Z-statistic = 3.43  

Answer : Value of calculated z-statistic is

              C.       3.43

d)

p-value      
For z = 3.43, we find the Right Tailed p-value using Excel function NORM.S.DIST      
p-value = 1 - NORM.S.DIST(3.4284, TRUE)      
p-value = 0.0003      

Answer : p-value is

              A.       0.0003

e) Decision
0.0003 < 0.05
that is p-value <= α
Hence we REJECT Ho

Answer : Conclusion :

      B.      Reject Ho

                and conclude there is sufficient evidence to support the

                claim that dyspepsia occurs at a

                higher rate among Viagra users than those who do not use Viagra