In the article “Comparable specificity of two commercial tuberculin reagents in persons at low risk for tuberculosis infection” published in the Journal of the American Medical Association (Villarino et al., 1999), the specificity of skin testing for tuberculosis with the reagents Aplisol and Tubersol was investigated. Use the information in Table 4.26, containing a summary of the ???? = 1555 participants not infected with tuberculosis in this study, to estimate the

(a) relative risk,

(b) odds ratio.