\f9. lilil'hat addttional information would you need to use model A to estimate the mean head circumference for babies born to mothers who had toxemia? a. The 9596 CI for the slope of the toxemia indicator. b. The RP? value for the simple linear regression model. c_The intercept for the simple linear regression model. cl. The p-value for testing Ho: beta1=D. where beta'l is the (population level} slope for toxemia. 9. lilifhlch of the following statements best describes the unadjusted mean difference {and 95% Cl) |n head circumference for lnfarrts whose mothers had toxemia versus Infants whose mothers did not have toxemia? a. Infants born to mothers who had toxemia had average head circumference of 0.82 cm greater on average than infants born to mothers who did not have toxemia {95% [II 4142 cm to 2.06 cm}. b. Infants born to mothers who had toxemia had average head circumference of 0.82 cm smaller on average than infants born to mothers who did not have toxemia {95% Cl 2.06 cm to 0-421- c. The estimated unadjusted mean difference in head circumference {and conesponding 95% condence interval] cannot be estimated without the intercept from the simple linear regression model of head circumference regressed on toxemia. d. The mean difference in average head circumferences is statistically signicant [0:13.051 as the 95% Cl does not include 0. 10. The estimated unadjusted relationship between head circumference and toxemia ls 0.32 cm [95% CI 43.42 to 2.06); this same compartson adjusted for gestational age is 1.41 cm {95% (3123 to 0.59]. The best explanation for this difference In the unadjusted and adjusted resus ls: a. Uncertainty from sampling variability in each of the two estimates. b. There is an interaction between gestational age and toxemia. c. The relationship between head circumference and toxemia is not linear. d. Gestational age is related to both head circumference and toxemia