To request a T-test on column proportions, type:

after the tab or l statement. Use propcorr to apply a continuity correction to the numerator of the proportion’s T-value.

This test looks at each row of the table independently and compares pairs of columns to test whether the proportion of respondents in one column is significantly different from the proportion in the other. For each pair in which the difference between the columns is significant, the ID of the smaller column is printed beside the figures in the larger column. For example, if you compare columns A and B, and proportion A is found to be significantly smaller than proportion B, the letter A is printed beside the figures in column B.

If two confidence levels have been defined, the ID is shown in uppercase if the test was significant at the higher level, or in lowercase if it was significant at the lower level.

The T-test is a two-tailed test. You can check which side of the curve the T statistic is on by running the test with one of the options tstatdebug or debug and looking in the tstat.dmp file. Negative values are on the left of the curve and positive values are on the right.

You can run this test by itself or with a T-test on column means.

With a T-test on column proportions, either on its own or with a T-test on column means, a continuity correction can reduce the difference between the two proportions compared. It is applied to the numerator of the proportion’s T-value. If the difference between the two proportions is positive, Quantum subtracts the correction value from the difference. If the difference is negative, Quantum adds the correction value to the difference.