Figure 2.

Mean impedance vectors with their 95% confidence ellipses at the screening visit, by previous contraception method. Mean impedance vectors with their 95% confidence ellipses at the screening visit. Labels to the vectors represent three groups according to the previous contraception method, vector a from 92 subjects following no method, vector b from 40 subjects taking oral contraceptives, and vector c from 41 subjects using barrier methods. Overlapping confidence ellipses indicate a comparable distribution of vectors among groups.