Advice: Paired t Test
PAIRED t TEST: This is listed in the parametric methods section of the analysis menu. With paired studies each individual is acting as their own control therefore you have reduced inter-individual variability leaving most of the error due to measurement. Furthermore this error tends to normality when we are considering differences and using a large sample. Seek statistical advice if you plan to use transformations to "normalise" your data. Wilcoxon's signed ranks test is the nonparametric alternative.