Would the demand condition be the independent variable and nominal? then the response time the DV and it would be interval? (can response time be negative so interval?) and then music condition IV with 3 levels and scale of measurement would be ordinal?

700 NM LIM RESPONSE TIME (MILLISECONDS) 650- HIM 550 500 450 LOW DEMAND HIGH DEMAND Figure 1. Reaction time during a driving simulator under low and high demand and different music conditions (NM = no music, LIM = low-intensity music, HIM = high-intensity music). Error bars represent standard error of the mean