riskratio {fmsb} R Documentation

## Calculate risk ratio and its confidence intervals

### Description

Calculate risk ratio (a kind of relative risk) and its confidence intervals based on approximation, followed by null hypothesis (risk ratio equals to 1) testing.

### Usage

` riskratio(X, Y, m1, m2, conf.level=0.95, p.calc.by.independence=TRUE) `

### Arguments

 `X` The number of disease occurence among exposed cohort. `Y` The number of disease occurence among non-exposed cohort. `m1` The number of individuals in exposed cohort group. `m2` The number of individuals in non-exposed cohort group. `conf.level` Probability for confidence intervals. Default is 0.95. `p.calc.by.independence` Logical. If TRUE, calculating p-value by testing the null-hypothesis of independence between exposure and disease. Otherwise, calculating p-value by inverse-function of confidence intervals calculation (the result becomes the same as the vcd package). Default TRUE.

### Value

 `estimate` Calculated point estimate of risk ratio. `conf.int` A numeric vector of length 2 to give upper/lower limit of confidence intervals. `p.value` The significant probability of the result of null-hypothesis testing.

### References

Rothman KJ (2012) Epidemiology: An Introduction. 2nd Ed., Oxford University Press, Oxford.

### Examples

``` res <- riskratio(5, 10, 90, 90)
str(res)
print(res)
riskratio(12, 5, 18, 17)
riskratio(12, 5, 18, 17, p.calc.by.independence=FALSE)
```

[Package fmsb version 0.7.0 Index]