Description Usage Arguments Details Value Author(s) References See Also Examples
Tests for independence where each row of the rx2 table is compared to the exposure reference level and test of independence two-sided p values are calculated using mid-p xxact, and normal approximation.
1 2 | rate2by2.test(x, y = NULL, rr = 1,
rev = c("neither", "rows", "columns", "both"))
|
x |
input data can be one of the following: r x 2 table where first column contains disease counts and second column contains person time at risk; or a single numeric vector for counts followed by person time at risk |
y |
vector of person-time at risk; if provided, x must be a vector of disease counts |
rr |
rate ratio reference value (default is no association) |
rev |
reverse order of "rows", "colums", "both", or "neither" (default) |
Tests for independence where each row of the rx2 table is compared to the exposure reference level and test of independence two-sided p values are calculated using mid-p xxact, and normal approximation.
This function expects the following table struture:
1 2 3 4 5 6 |
The reason for this is because each level of exposure is compared to the reference level.
If the table you want to provide to this function is not in the
preferred form, just use the rev
option to "reverse" the rows,
columns, or both. If you are providing categorical variables (factors
or character vectors), the first level of the "exposure" variable is
treated as the reference. However, you can set the reference of a
factor using the relevel
function.
Likewise, each row of the rx2 table is compared to the exposure reference level and test of independence two-sided p values are calculated using mid-p exact method and normal approximation.
This function can be used to construct a p value function by testing the MUE to the null hypothesis (rr=1) and alternative hypotheses (rr not equal to 1) to calculate two-side mid-p exact p values. For more detail, see Rothman.
x |
table that was used in analysis |
p.value |
p value for test of independence |
Tomas Aragon, aragon@berkeley.edu, http://www.phdata.science
Kenneth J. Rothman and Sander Greenland (2008), Modern Epidemiology, Lippincott Williams and Wilkins Publishers
Kenneth J. Rothman (2002), Epidemiology: An Introduction, Oxford University Press
1 2 3 4 5 6 7 8 9 10 | ##Examples from Rothman 1998, p. 238
bc <- c(Unexposed = 15, Exposed = 41)
pyears <- c(Unexposed = 19017, Exposed = 28010)
dd <- matrix(c(41,15,28010,19017),2,2)
dimnames(dd) <- list(Exposure=c("Yes","No"), Outcome=c("BC","PYears"))
##midp
rate2by2.test(bc,pyears)
rate2by2.test(dd, rev = "r")
rate2by2.test(matrix(c(15, 41, 19017, 28010),2,2))
rate2by2.test(c(15, 41, 19017, 28010))
|
$x
bc pyears
Unexposed 15 19017
Exposed 41 28010
$p.value
Outcome
Predictor midp.exact wald
Unexposed NA NA
Exposed 0.03545742 0.03736289
$x
Outcome
Exposure BC PYears
No 15 19017
Yes 41 28010
$p.value
two-sided
Exposure midp.exact wald
No NA NA
Yes 0.03545742 0.03736289
$x
Outcome
Predictor Count Person-time
Exposed1 15 19017
Exposed2 41 28010
$p.value
two-sided
Predictor midp.exact wald
Exposed1 NA NA
Exposed2 0.03545742 0.03736289
$x
Outcome
Predictor Cases Person-time
Exposed1 15 19017
Exposed2 41 28010
$p.value
two-sided
Predictor midp.exact wald
Exposed1 NA NA
Exposed2 0.03545742 0.03736289
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