Anastasia Ivanova | Vance Berger |
University of North Carolina at Chapel Hill | National Cancer Institute |
aivanova@bios.unc.edu | vb78c@nih.gov |
Here we analyze a pair of 2´2 tables, resulting from a study with a single binary endpoint when the analysis calls for stratification. Consider the data from Kurtiz et al. (1988).
|
Some initial pain |
|
Lots of initial pain |
||
|
5–8 |
0–4 |
|
5–8 |
0–4 |
Placebo |
4 |
14 |
Placebo |
11 |
15 |
A & B |
0 |
19 |
A&B |
1 |
25 |
The software written in Splus implements several tests
that can be used to analyze a pair of 2x2 contingency
tables
The last two tests had been developed by the authors and have an advantage of being nonlinear rank tests.
Function MH2x2.test plots extreme and rejection regions
(one-sided, nominal alpha=0.05), and calculates
the p-value.
Function Smirnov2x2.test plots extreme and rejection
regions (one-sided, nominal alpha=0.05), and calculates
the p-value.
Function chull2x2.test
plots extreme and rejection regions (one-sided, nominal
alpha=0.05), and calculates the p-value.
Downloads
The programs are developed
in S-PLUS 4.0 for Microsoft Windows.
The following downloads include the source functions. Create a
directory, say CATEGORICAL, for the program. Download and extract the appropriate
file there. For example, to
install the function MH2x2.test, source the MH2x2.s
file into S-PLUS via
source("<path>/
MH2x2.s")
where <path> is the directory in which the program files are located. Or just copy the function and paste it into S-PLUS.
TRY IT
> MH2x2.test(4, 14, 0, 19, 11, 15, 1, 25)
> Smirnov2x2.test(4, 14, 0, 19, 11, 15, 1, 25)
> chull2x2.test(4, 14, 0, 19, 11, 15, 1, 25)