Red meat and heart disease. Refer to the study presented at ESC Preventive Cardiology 2021 that explored the link between red meat and heart disease, Exercise 9.12 (p. 533). Recall that the study randomly assigned 19,408 participants to three different heart imaging measures: cardiovascular magnetic resonance (CMR), novel CMR radiomics, and measuring the elasticity of the blood vessels. All three heart imaging measures reported an association between greater intake of red meat and worse imaging measures of heart health. Say participants were randomly distributed into four groups: Group A participants would consume red meat in high quantities; Group B participants would consume red meat in medium quantities; Group C participants would consume red meat in low quantities; and Group D participants would consume no red meat for six months. The imaging measures of heart health before and after this six-month period were recorded using the CMR method and an output score was assigned to each participant on a 10-point rating scale, where low scores indicated poor heart function.

a. Write a model for the mean heart health imaging measure score, E1y2, as a function of the four groups (A, B, C, or D). Use Group D as the base level.

b. Interpret the b’s in the model, part

a. c. Recall that the researchers’ found worse heart health imaging measures the greater the intake of red meat. On the basis of this result, determine the order (bigger or smaller) of the b’s in the model, part a.