In the article “Passive cigarette smoke exposure of infants” published in the Archives of Pediatric and Adolescent Medicine (Ownby et al., 2000), the authors reported the estimated regression coefficients and standard errors given in Table 9.28 for a regression model relating the logarithm of an infant’s cotinine–creatinine ratio for

???? = 97 infants. Use the information in Table 9.28 to answer the following:

(a) Compute the value of the ???? statistic for each of the regression coefficients.

(b) Approximate the ????-value associate with each of the ???? statistics in part (a).

(c) Does it appear that the sex of a child is important in predicting the logarithm of an infant’s cotinine–creatinine ratio? Explain.