A study was done to investigate whether a relationship existed between HPV (human papillomavirus) status and HIV infection status. HPV status and HIV infection status were obtained for 97 women.
Table of hpv by hiv 


hpv 
hiv 

Frequency 
Seropositive/Symptomatic 
Seropositive/Asymptomatic 
Seronegative 
Total 
Positive 
23 
5 
10 
38 
Negative 
10 
14 
35 
59 
Total 
33 
19 
45 
97 
Statistic 
DF 
Value 
Prob 

ChiSquare 
2 
19.6478 
<.0001 
Likelihood Ratio ChiSquare 
2 
19.8286 
<.0001 
MantelHaenszel ChiSquare 
1 
17.0081 
<.0001 
Phi Coefficient 
0.4501 

Contingency Coefficient 
0.4104 

Cramer's V 
0.4501 
Fisher's Exact Test 


Table Probability (P) 
<.0001 
Pr <= P 
<.0001 
Question 1
Which test is appropriate for these data, chisquare or Fisher's Exact test?






Question 2
What are the test statistic, degrees of freedom, and pvalue for the test you chose (chisquare or Fisher's Exact test)?







Question 3
How would you present your conclusion to a "layperson" (i.e., someone who has no knowledge of statistics)?







Question 4
What is the correct calculation of the degrees of freedom (d.f. = 2) for this contingency table?







1) Here we will use chisquare test as here we want to test homogeneity also the variables here are categorical.
Option (a) is correct.
Q2)
From the table test statistics is 19.6478
degrees of freedom is 2
and p value <0.0001
So, Option (C) is correct.
Q3)
Since, our pvalue<0.0001<0.05. So, we reject the null hypothesis and conclude that there is significant association between the HPV and HIV status.
Option (B) is correct.
Q4)
In Chisquare test degrees of freedom is given as
(r1)*(c1) = (21)(31) = 1*2
= 2
Option (C) is correct.
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