Fischer y chi

# A randomised clinical trial on the use of intermediate bonding on the retention of fissure sealants in children
# DOI: 10.1111/ipd.12165


# Overall
overall <- matrix(c(179, 154, 16, 41),ncol=2,byrow=TRUE)
colnames(overall) <- c("Bonded","Non-bonded")
rownames(overall) <- c("Sucess","Failure")
overall <- as.table(overall)
overall

##         Bonded Non-bonded
## Sucess     179        154
## Failure     16         41

# Maxillary
maxillary <- matrix(c(93, 73, 4, 22),ncol=2,byrow=TRUE)
colnames(maxillary) <- c("Bonded","Non-bonded")
rownames(maxillary) <- c("Sucess","Failure")
maxillary <- as.table(maxillary)
maxillary

##         Bonded Non-bonded
## Sucess      93         73
## Failure      4         22

# Mandibular
mandibular <- matrix(c(87, 82, 11, 16),ncol=2,byrow=TRUE)
colnames(mandibular) <- c("Bonded","Non-bonded")
rownames(mandibular) <- c("Sucess","Failure")
mandibular <- as.table(mandibular)
mandibular

##         Bonded Non-bonded
## Sucess      87         82
## Failure     11         16

# Analysis with Fisher test

FisherOverall <- fisher.test(overall) # p-value = 0.000496
FisherMax <- fisher.test(maxillary) # p-value = 0.0001013
FisherMand <- fisher.test(mandibular) # p-value = 0.4075

# Analysis with chi2
ChiOverall <- chisq.test(overall) # X-squared = 11.835, df = 1, p-value = 0.0005813
ChiMax <- chisq.test(maxillary) # X-squared = 13.271, df = 1, p-value = 0.0002696
ChiMand <- chisq.test(mandibular) # X-squared = 0.68727, df = 1, p-value = 0.4071

Resultados

con Fisher

FisherOverall 

## 
##  Fisher's Exact Test for Count Data
## 
## data:  overall
## p-value = 0.000496
## alternative hypothesis: true odds ratio is not equal to 1
## 95 percent confidence interval:
##  1.55843 5.90686
## sample estimates:
## odds ratio 
##   2.970394

FisherMax 

## 
##  Fisher's Exact Test for Count Data
## 
## data:  maxillary
## p-value = 0.0001013
## alternative hypothesis: true odds ratio is not equal to 1
## 95 percent confidence interval:
##   2.222426 28.956859
## sample estimates:
## odds ratio 
##   6.943379

FisherMand 

## 
##  Fisher's Exact Test for Count Data
## 
## data:  mandibular
## p-value = 0.4075
## alternative hypothesis: true odds ratio is not equal to 1
## 95 percent confidence interval:
##  0.6283966 3.9041001
## sample estimates:
## odds ratio 
##   1.539824

Con Chi

ChiOverall 

## 
##  Pearson's Chi-squared test with Yates' continuity correction
## 
## data:  overall
## X-squared = 11.835, df = 1, p-value = 0.0005813

ChiMax 

## 
##  Pearson's Chi-squared test with Yates' continuity correction
## 
## data:  maxillary
## X-squared = 13.271, df = 1, p-value = 0.0002696

ChiMand 

## 
##  Pearson's Chi-squared test with Yates' continuity correction
## 
## data:  mandibular
## X-squared = 0.68727, df = 1, p-value = 0.4071