Advice: Wilcoxon's Signed Ranks Test
Paired
Interval
Small to medium sample
Non-normal distribution
WILCOXON'S SIGNED RANKS (MATCHED PAIRS) TEST: This is listed under the nonparametric methods section of the analysis menu. Please remember that more often than not differences between pairs tend to normality and the more sensitive paired Student t test many be appropriate for your analysis. If there is any doubt or you are considering using transformed differences then please seek statistical advice.