Is A the correct answer?

6. The 2010 National Hospital Ambulatory Medical Care Survey (NHAMCS) is a national (United States) sample survey of visits to hospital outpatient and emergency departments. This survey was conducted by the National Center for Health Statistics. In this exercise, multiple linear regression will be used to examine factors associated with patient waiting time (in minutes) of persons admitted to the Emergency Departments (EDS) of participating hospitals in 2010. The average waiting time reported by the over 27,000 survey participants is 56.3 minutes (s= 78.7 minutes, with a range of 0 to 1,335 minutes). The linear regression that relates average time to visitors' sex, racial identity (white (reference), black, other), insurance type (private vs not private), and systolic blood pressure (mmHg) is of the form: 9 = ii, + 31x1 + 32x2 + 33x3 + 3m + iisxs where x1=1 for female (0 for male); x; =1 for black, x3 = 1 for other racial identity; x4=1 for private insurance, 0 for nonprivate; x5 = systolic blood pressure (mmHg). The regression equation with the actual intercept and slope estimates is: SI = 62.6 + 2.4x1 + 18.8x2 + 1.7x3 + 7.9x4 + 0.05x5 - What is the assumed nature of the relationship between waiting times and watolic blood pressure (SBP) for the regression model presented above? a. The unadjusted association between waiting times and SBP is approximately linear. b. The unadjusted association between waiting times and SBP not linear. c. The sex, insurance type, and racial identityadjusted association between waiting times and SBP is approximately linear. d. The sex, insurance type, and racial identityadjusted association between waiting times and SBP is not linear