Figure 1: Correlation analysis between STI and HIV testing during the previous three months.

The chart represents coordinate variables (positive or negative response) and person (age) for principal components F1 and F2. F1 and F2 gave 88% of the total information of the responses to the questionnaire. F1 gave 75% of the information measuring positive and negative responses of all students for having done an HIV test during the previous three months; positive and negative responses of female students (FS) and only negative responses of male students (MS) for having STI during the previous three months. These parameters are positively correlated. F2 gave 13 % of the information link to positive responses of only MS for having STI infection during the previous three months.