P-values for a T-test on column proportions

Quantum generates a P-value for each pair of columns tested in each row. These show the actual level of significance. So that all these values may be viewed in a legible form, Quantum writes them out to a separate log file, tstat.dmp. This file is laid out so that there is one display column per pair of columns tested, and one row per row tested. Headings indicate which display column refers to each pair, and the side text for each row (truncated if necessary) is printed at the side of each row.

	A/B	A/C	A/D	B/C	B/D	C/D
Effect bas	1.000	1.000	1.000	1.000	1.000	1.000
18-24	0.964	0.862	0.629	0.811	0.562	0.754
25-34	0.400	0.356	0.263	0.840	0.664	0.830
35-44	0.212	0.185	0.547	0.005	0.054	0.482
45-54	0.452	0.455	0.551	0.106	0.155	0.889
55-64	0.038	0.850	0.340	0.023	0.310	0.255

The P-values in this example show that you can have confidence at the 96.2% level that there is a difference between the proportions of respondents aged 55-64 in the A and B columns.

Lines in the T statistics log file may be a maximum of 160 characters long, and a minimum of five characters is required for each P-value. If a table has many columns and you have requested T‑tests for many pairs of columns, Quantum might not have enough space to write all the information it needs in one line. If this happens, error messages like this appear:

This does not affect the validity of the T statistics in the table; it just indicates the problem in writing to the log file.