Relationship between family income and change in exhaled nitric oxide (FeNO) in response to the acute psychosocial stressor. Top panel depicts data for children with asthma. Bottom panel depicts data for healthy children. Because measurements of change in response to a stressor need to take into account baseline values, change scores were regressed onto baseline values. The residualized score represents the variance in pre- to post-FeNO scores that is left over once the variability due to baseline FeNO levels has been removed. These residuals are scaled such that the mean for the sample equals 0 and the standard deviation of the residuals equals 1. Hence Figure 1 depicts residualized FeNO values on the y-axis, and the graph indicates the relationship between family income and the change in FeNO not due to baseline FeNO levels. Associations between FeNO and family income are significant in children with asthma (b=−2.97, SE=1.07, p=.01), but not among healthy children (b=.51, SE=.61, p=.42).