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Figure 2 Number of Subjects Required in Crossover and Parallel Designs for Given FMD Effect

Relation between effect on maximum percent change in flow-mediated dilation (FMD) (%) and number of subjects required in crossover and parallel study designs at 80% power and 5% significance, 4 to 6 h and 3 months apart with 3 monitoring strategies: 1, 2, or 4 measures pre- and post-treatment.