This report covers the statistical analysis of the variables affecting hydrocarbon emissions during Stage II refueling operations for vapor balance recovery systems done by the staff of Research Triangle Institute, Research Triangle Park, NC. The purpose of the analysis was to assist the Environmental Protection Agency (EPA) in developing compliance test procedures for vapor balance recovery systems at service stations. In particular, the analysis was performed in order to determine the number of vehicles needed to establish a baseline curve for the system and to estimate and test, statistically, the significance of the estimated vapor emission rate.