# odds.ratio

From HH v2.1-15
0th

Percentile

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

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.

Keywords
hplot, htest
##### Usage
odds.ratio(x, alpha = 0.05)

plot.odds.ratio(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. odds.ratio requires a single number in the range [0,1]. plot.odds.ratio 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.
...
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

• plot.odds.ratio draws a plot and invisibly returns the same list as odds.ratio for the first value of alpha. odds.ratio returns the list:
• p1, p2proportion of each row total observed in the first column.
• omega1, omega2odds for each row, p/(1-p)
• psihatodds ratio, omega2/omega1
• s.ln.psihatstandard deviation of ln(psihat)
• ci.ln.psihatconfidence interval for ln(psihat) using normal approximation
• ci.psihatconfidence interval for psihat calculated ase p(ci.ln.psihat)
• prob1seq(0,1,.05), set of p1 values for plotting.
• odds1p1/(1-p1)
• odds2odds for the second row needed to retain psihat with the specified odds1, calculated as odds1*psihat.
• ci.odds2confidence interval for odds2
• prob2odds2 / (odds2+1)
• ci.prob2ci.odds2 / (ci.odds2+1)

##### References

Heiberger, Richard~M. and Holland, Burt (2004b). Statistical Analysis and Data Display: An Intermediate Course with Examples in S-Plus, R, and SAS. Springer Texts in Statistics. Springer. ISBN 0-387-40270-5.

##### Aliases
• odds.ratio
• plot.odds.ratio
##### Examples
glasses <- read.table(hh("datasets/glasses.dat"), header=FALSE)

glasses <- matrix(unlist(glasses),
nrow=2,
dimnames=list(
c("glasses","no.glasses"),
c("delinq","non.del")))

## draw the iso-odds ratio plot with 50\% CI and 95\% CI,
## invisibly return the 95\% CI
plot.odds.ratio(glasses)
Documentation reproduced from package HH, version 2.1-15, License: GPL (>= 2)

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