Question

1. Are there any reference cells in this problem? If so, what are they?
2. 1. No, there are no reference cells.
   2. Yes, reference cells are high CAT, ever smoked, abnormal ECG, and high BP.
   3. Yes, reference cells are normal CAT, never smoked, normal ECG, and not high BP.
   4. Yes, reference cells are higher age, higher cholesterol, higher DBP, and higher SBP.
   5. Both b and d
   6. Both c and d

2. How many dummy variables need to be included in the model for high blood pressure, HPT?
3. 1. 0
   2. 1
   3. 2
   4. 3
   5. 4

Consider the follow-up study data from the Evans County (Georgia) Heart Disease Study described by Cassels (1971). The data pertain to a cohort of 609 healthy white males between the ages of 40 and 76 who were residents of Evans County in 1960. The cohort was followed for 7 were identified, The level of years, after which new cases of coronary heart disease (CHD) circulating catecholamine (CAT) is the exposure variable of interest (defined as 1 = high and 0 normal). The purpose of the study measured in 1960) and the subsequent 7-year incidence of CHD controlling for other potential confounders. The data are summarized below = was to assess the putative association between CAT (as High CAT Low CAT 44 CHD 27 71 No CHD 95 443 538 122 487 609 All other variables of interest for this example include: AGE: age (in years) CHL: cholesterol level (mg/dl) SMK: smoking status (1 = ever smoked or 0 ECG: electrocardiogram abnormality (1 yes or 0 no) DBP: diastolic blood pressure (mm Hg) SBP: systolic blood pressure (mm Hg) HPT: high blood pressure defined as having SBP 160 or DBP2 95 (1 yes or 0 no) never smoked) = Testing Global Null Hypothesis: BETA- Test chi-Square Pr Chisq DF Likelihood Ratio 39.9582

Answer 1

Yes. There are reference cells in this problem. Both options b and d are reference cells.

Answer : e.

HPT= 1, if SBP>=160 OR DBP>=95

=0, OTHERWISE

Hence 1 dummy is needed.

Answer : b