Is it statistically significant? The chi-square test

2.4 Determining threshold fold differences where intrapatient fold-differences should have been zero (goal-negative) Every gene had four calculated intrapatient LFD. Since the same samples were used in the duplicated measurements, all the intrapatient LFD should have been zero (i.e. fold difference of one). Instead, we found a bell-shaped ... ................
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