I found a free online class that's being offered by the EdX University.
Here's the link to the class: PH207x: Health in Numbers: Quantitative Methods in Clinical & Public Health Research

The class is open to the public and you receive a certificate of completion at the end. This time it will be offered by HarvardX by to professors from the Harvard School of Public Health. 

Sharing and article on Sex-trafficking and HIV risk, in the Tijuana-San Diego border. Enjoy. 
http://gph.ucsd.edu/research/sex_trafficking_HIV.shtml