odds.ratio: Calculate or plot the odds ratio for a 2x2 table of counts.

In HH: Statistical Analysis and Data Display: Heiberger and Holland

Calculate or plot the odds ratio for a 2x2 table of counts.

Description

Calculate or plot the odds ratio for a 2x2 table of counts. The plot shows the confidence intervals on the probability of row2 for fixed odds ratio and specified probability for row1.

Usage

OddsRatio(x, alpha = 0.05)

plotOddsRatio(x,
              ylab="prob(col1 | row1)",
              xlab="prob(col1 | row2)",
              alpha=c(.50, .05),
              col=trellis.par.get("superpose.line")$col,
              lwd=trellis.par.get("superpose.line")$lwd,
              lwd.reference=1,
              ...)

plotOddsRatio.base(x,
 ylab = "prob(col1 | row1)", xlab = "prob(col1 | row2)",
 alpha = c(0.05, 0.5),
 legend.x=1.05,
 oma=c(0,0,0,5), ...)

Arguments

x	2 x 2 table of counts
alpha	Significance levels of test. OddsRatio requires a single number in the range [0,1]. plotOddsRatio accepts more than one number on the range [0,1] and draws confidence lines at each value.
xlab, ylab	x- and y-labels for the plot Sensible defaults are generated.
col, lwd	Colors and linewidths to be used in the graph.
lwd.reference	linewidth for reference line.
...	other arguments, currently ignored.
legend.x	x position of left-hand side of legend.
oma	outer margin par()$oma, needed to make room for legend.

Value

plotOddsRatio returns a lattice object.

The older plotOddsRatio.base draws a plot with base graphics and invisibly returns the same list as OddsRatio returns for the first value of alpha.

OddsRatio returns the list:

p1, p2	proportion of each row total observed in the first column.
omega1, omega2	odds for each row, p/(1-p)
psihat	odds ratio, omega2/omega1
s.ln.psihat	standard deviation of ln(psihat)
ci.ln.psihat	confidence interval for ln(psihat) using normal approximation
ci.psihat	confidence interval for psihat calculated ase p(ci.ln.psihat)
prob1	seq(0,1,.05), set of p1 values for plotting.
odds1	p1/(1-p1)
odds2	odds for the second row needed to retain psihat with the specified odds1, calculated as odds1*psihat.
ci.odds2	confidence interval for odds2
prob2	odds2 / (odds2+1)
ci.prob2	ci.odds2 / (ci.odds2+1)

Author(s)

Richard M. Heiberger <[e-mail]>

References

Heiberger, Richard M. and Holland, Burt (2015). Statistical Analysis and Data Display: An Intermediate Course with Examples in R. Second Edition. Springer-Verlag, New York. https://link.springer.com/book/10.1007/978-1-4939-2122-5

Examples

data(glasses)

## draw the iso-odds ratio plot with 50% CI and 95% CI,
plotOddsRatio(glasses)

## return the 95% CI information
OddsRatio(glasses)

## draw the iso-odds ratio plot with 50% CI and 95% CI,
## invisibly return the 95% CI information
plotOddsRatio.base(glasses)

HH documentation built on May 29, 2024, 6:24 a.m.