Question 2

Flame retardants are often applied to office furniture, but as furniture ages, chemicals applied to furniture can end up in the air or dust in the surrounding areas leading to potentially harmful exposures of people to these chemicals.

A cross-sectional survey was used to examine the association between flame retardants in offices in a large building and the prevalence of self-reported migraine headaches among office workers in the building. Participants were categorized as high exposure or low exposure to flame retardants based on the size and density of foam in furniture in their office. Study staff conducted evaluations of flame retardant levels in each office and then interviewed workers to assess their history of recent migraine headaches.

1. The study authors reported that workers in offices with high levels of exposure were more likely to report having migraine headaches as compared to workers in offices with low levels of exposure and provide the data below. Use riskratio.wald to calculate the prevalence ratio and 95% confidence interval. Interpret the results in a sentence or two. (Note: You do not have to attach anything, since you do not have a raw data set. (10 points)

	D- (no migraine)	D+ (migraines)	Row Totals
E- (low exposure)	380	20	400
E+ (high exposure)	540	60	600