This section deals with statistics and how significant differences are marked in QPSMR Companion.
Please refer to our Overview of statistics page for more information.
If respondent weighting has been applied to a table, the program maintains weighted and unweighted counts for all cells and is able to use the unweighted figure, where appropriate, when calculating statistics. If you believe your weighting procedures to be relevant and correct, then you can still produce meaningful statistics.
Various formats are provided to remove the “Weighting effects” if required. With these formats the “Effective base” is also kept for all cells and is used in statistics instead of the unweighted base where appropriate.
You can perform Z tests or t-tests on tables with normal rows using format SIG. Each row is tested independently.
For tables with score values assigned to the rows it is better to test the mean scores using a t-test.
For tables with a value (integer or float) as the rows it is also better to use a t-test on the average value.
For more information: Statistics formats settings
You can see some of the formulae used by Companion on the Formulae page.
For a description of one tailed tests, please visit Companion’s One tail or two tail page.