Introduction to Stata 8 - (GRIPS

tabi
[R] tabulate
tabi is an 'immediate' command (see section 15.5) enabling you to analyse a table without
first creating a data set. Just enter the cell contents, delimiting the rows by \ (backslash):
. tabi 10 20 \ 17 9 , chi exact
| col
row | 1 2 | Total
-----------+----------------------+----------
1 | 10 20 | 30
2 | 17 9 | 26
-----------+----------------------+----------
Total | 27 29 | 56
Pearson chi2(1) = 5.7308 Pr = 0.017
Fisher's exact = 0.031
1-sided Fisher's exact = 0.016
epitab
The commands in the epitab family perform stratified analysis. Here I show cc.
. cc case exposed , by(age) woolf
[ST] epitab
Maternal age | OR [95% Conf. Interval] M-H Weight
----------------+-------------------------------------------------
chi2 = 0.7105
Test that combined OR = 1:
Mantel-Haenszel chi2(1) = 5.81
Pr>chi2 = 0.0159
All procedures perform stratified analysis (Mantel-Haenszel). cc gives odds ratios for each
stratum and the Mantel-Haenszel estimate of the common odds ratio. The test of homogeneity
tests whether the odds ratio estimates could reflect a common odds ratio.
Command Measure of association Immediate command
ir Incidence rate ratio, incidence rate difference iri
cs Cohort studies: Risk ratio, risk difference csi
cc Case-control studies: Odds ratio cci
tabodds
mhodds
Odds ratio, several exposure levels. Trend test
Odds ratio, several exposure levels. Trend test
mcc Odds ratio (matched case-control data) mcci
If you want to stratify by more than one variable, the following command is useful:
egen racesex=group(race sex)
cc case exposed , by(racesex)
The immediate commands do not perform stratified analysis; an example with cci. Just
enter the four cells (a b c d) of the 2×2 table:
cci 10 20 17 9 , woolf
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