Evaluate the collective function of references cited together in a given text segment.
Classify their combined role into one of the following categories: 'method', 'background', or 'result'.

Text:To determine the significance of the change from baseline of each lipid species, subclass, and class during the postprandial period (for dairy or soy meals) we performed the nonparametric Friedman test on the plasma concentration values and corrected for multiple comparisons by using the Benjamini-Hochberg method (23).
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